zks7

Flying Tiger - Tohatsu 9.8 HO motor

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I am having some repeating problems with a 2 year old Tohatsu 9.8 motor. Are there any chronic repetitive problems with this motor?

 

I have spent about $1300 on the repairs in hte past few months for various "doagnosis". 

 

Tune up, replace impeller,

The motor is difficult to start: Replace the electric choke module and linkage

Field rebuilt the carburetor.

 

  • Motor is hard to start
  • When it starts, it runs at high revs.
  • As I back off it dies.
  • If I do get it to start, it runs well until I back off the throttle..
  • Then it dies, and will not restart.
  • The mechanic who has been out to the boat repairing it says it is a "bad motor for the environment".

 

Sounds to me like he cannot fix it wants to get out of working on it anymore...

 

 

  1. Former owner says that he did not have this problem, but he replaced the carburetor every year and everything was fine.
  2. Is anyone having this problem?
  3. Is there a solution (you have found)?
  4. Does anyone have a replacement motor they have used that will fit the footprint of the engine cavity?

 

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I have a Tohatsu 6 on my S2, 4600 ibs. Has served me well.

I have had a problem that if the motor dies, very hard to restart.

It was suggested to give it 1/2 choke. Starts back up with 1 pull.

I find that with Tohatsu owners, they either love them or hate them.

 

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Has the fuel pump been replaced? The ethanol fuel will ruin the fuel pump diaphragm over time.  I stopped running ethanol fuel and have not had any problems with the carb. A common thing other people do with their outboards is unplug the fuel line and let the engine run dry to minimize fuel gumming up in the carb. During the winter I also have a fan that blows warm dry air from the cabin into the engine compartment to minimize condensation. Not sure about 2020 prices, but a new tohatsu will probably be under 2K. Fitting another brand will difficult and require a different remote which add to expenses if the motor fits. 

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6 hours ago, zks7 said:

I am having some repeating problems with a 2 year old Tohatsu 9.8 motor. Are there any chronic repetitive problems with this motor?

 

I have spent about $1300 on the repairs in hte past few months for various "doagnosis". 

 

Tune up, replace impeller,

The motor is difficult to start: Replace the electric choke module and linkage

Field rebuilt the carburetor.

 

  • Motor is hard to start
  • When it starts, it runs at high revs.
  • As I back off it dies.
  • If I do get it to start, it runs well until I back off the throttle..
  • Then it dies, and will not restart.
  • The mechanic who has been out to the boat repairing it says it is a "bad motor for the environment".

 

Sounds to me like he cannot fix it wants to get out of working on it anymore...

 

 

  1. Former owner says that he did not have this problem, but he replaced the carburetor every year and everything was fine.
  2. Is anyone having this problem?
  3. Is there a solution (you have found)?
  4. Does anyone have a replacement motor they have used that will fit the footprint of the engine cavity?

 

Ventilation. We had issues with the outboard in the tiger well until we improved ventilation. Fan working okay?

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The fan is working so the assumption is that it is operational to the requirements. 

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16 hours ago, Varan said:

Ventilation. We had issues with the outboard in the tiger well until we improved ventilation. Fan working okay?

We had annual issues with our 9.8 motor. We determined that our issue was ethanol fuel in a wet engine compartment. To correct, we started rebuilding the carburetor at the end of each season right after we began limping on or off the racecourse. After the second year, we started to by non-ethanol racing fuel and while closing up the boat, leaving the motor up high enough to keep the hatch open an inch or so. It's that last thing on the way off and we readjust first thing on the way back on so no one breaks the hatch. Since making those adjustments, the boat has been running well for four years with only regular maintenance.

If you think the issue is the fan, run the boat with the hatch open. That would tell you if you are having an issue with the air intake. The boat does much better sailing. :)

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We had troubles with the carburetor on the 9.8.  The carburetor bowl is made of an aluminum alloy that seems to react with fuel stagnating in the bowl.  What happens is that the aluminum bowl starts to sluff off a sand like material that clogs the jets.  My experience was that the idle jet was first to clog so that the engine would starve for fuel at idle but run when the throttle was opened.  Continuing to run the engine like that results in the second jet clogging after a while and the engine running erratically.  I had several mechanics look at it and none figured it out.  I only found out what the problem was from other FT10 owners.  There are only two bolts holding the carb to the engine and some owners can remove/replace the carb in minutes.  

The solution seems to be to run the carb dry after each use by removing the fuel line and running the engine until the carb bowl is dry.  A further precaution is not to use old fuel.  I use the 3 gal tank that came with the 9.8 and put new fuel in the tank at the beginning of the day going down to the boat - engine burns about 1 gal/hr so I just get a little more than a gal.  If the boat is going to sit for a while, I dump what fuel is in the 3 gal tank into my car and keep the tank dry.  I once left a couple gallons in the 3 gal tank for a couple of months and I poured the gas into a clear plastic jug - you could see water at the bottom of the jug.  If you are using a large fuel tank in the storage area behind the motor, I would suggest you stop.  There is definitely going to be water in that tank and you cannot remove the tank with the engine in the boat. 

Another solution adopted by some is that a new carb is about $100.  It is possible to have a spare carb and change the carb at the first sign of fuel starvation or erratic running - then take the old carb home to clean the jets.

The person to talk to about 9.8 carb issues is Clewless, FT10 owner in SD.

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Thank you for the information. We are struggling keeping the engine going. Did you ever replace the fuel pump?

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4 minutes ago, zks7 said:

Thank you for the information. We are struggling keeping the engine going. Did you ever replace the fuel pump?

No.  Never heard of anyone replacing fuel pumps.

Clearly your mechanic is thinking fuel starvation.  I bet the problem is the carb.

 

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It runs wide open and pretty fast. The issue is at idle speeds. It does sounds like the carb is fouled. But even more it might be that the fuel tank needs to be pulled/replaced and start over with a completely dry tank without the possibility of water or bad fuel?

 

And of course rebuilding the carb.

 

Where do you source the gaskets for the carb and fuel pump?

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5 minutes ago, zks7 said:

It runs wide open and pretty fast. The issue is at idle speeds. It does sounds like the carb is fouled. But even more it might be that the fuel tank needs to be pulled/replaced and start over with a completely dry tank without the possibility of water or bad fuel?

 

And of course rebuilding the carb.

 

Where do you source the gaskets for the carb and fuel pump?

If the engine will not idle and runs with the throttle (part or full) open  - then it is likely a clogged carb idle jet, which is common. 

Below floor fuel tank - The problem with the tank is you cannot remove it (and dump out water and old fuel) while the engine is in the boat.  The ethanol in the fuel pulls water vapor from the air and results in water in the fuel.  Consequently, your fuel tank is water trap.  To try and solve the problem, I installed a fuel filter and water separator.  But I was never happy about fuel going old and turning to varnish in the tank.   Also, I was never sure exactly how much fuel I had so I always had too much fuel to be safe.  

The Tohatsu 9.8 is a simple solid engine.   

Finding parts for the Tohatsu is as easy as finding M&Ms.  Many of the major engine brands in the 9.8 hp range - like Mercury 9.9 - are just rebranded Tohatsu engines.  Svendsens in Alameda is a Tohatsu dealer.  There is also a funky shop in Alviso that is a Tohatsu dealer and they do great work - at least they use to.  There is another dealer in Sausalito.   Dealers are listed on the Tohatsu website.

In taking the carb apart and cleaning, I was able to use the old gaskets.  

Removing and cleaning the carb is a job you can do.  If you have someone else do it, it would be good to watch.  You also want to see what is in the carb bowl.  The last time I opened one, it looked like there was a fine sand in the bowl.  A sure indicator the the jets are clogged.

If all else fails, the Tohatsu imported in Texas is a great guy and you should give him a call.  He was very responsive when I needed small linkage parts replaced under warranty when the do-nothing dealer I bought the motor from was of no help.

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13 hours ago, Team Subterfuge said:

No.  Never heard of anyone replacing fuel pumps.

Clearly your mechanic is thinking fuel starvation.  I bet the problem is the carb.

 

The fuel pump is worth replacing if it's several years old and you are using ethanol gas. Not hard to do and not expensive. If the diaphragm ruptures, every time you prime, fuel goes into the crankcase and can cause more serious problems. You will also see fuel starvation symptoms. This happened to me, but the engine at the time was  maybe 10 years old. I agree though, the carb is the most likely culprit and should be looked at first. The carb problems are typical of any small carburated engine. Rebuilding the carb is not hard to do on this engine either. Outside of the fuel pump issue, the engine has been great for me. I've done a lot of long wintertime deliveries with it.

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Bay area automobile fuel has too much ethanol in it for small engines. Long story why this is happening.  I switched to ethanol free fuel and have not had to rebuild a carburetor in our chase boat fleet in two years.  Sunnoco sells a product called Optima for small engines or av gas will work. night and day results.

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Thanks for the help. I am very aware (now) of the ethanol issues. Has anyone had any long term use of STA-Bil fuel stabilizer? Specifically if It was used with each filling of the tank. 

 

The problem on this end appears to have been two faulty carburetors. The idle circuit needle valves were both closed. One directly from the factory; the other from use? We found one that was working, took it apart and looked the spacing in the vlaves. 

 

It took 5 repair visits before we tried that last alternative. Will see how it runs and restarts this weekend.

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The only time I had any problems with my motor was ventilation related. The fan ran and everything appeared OK. It wasn't till I took the vent tubing off the fan, that I found the problem. Which was water sitting in the tubing, I emptied that out and in the process found an old plastic bag that had found its way in. Once the tube was clear no problem and a lot more airflow.. Might not be your problem but worth a look.

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Thanks for the suggestions.How did the water/bag gain access? We will check tubing this weekend. The engine ran fine at speed. We couldn't get it to idle. We replaced the carburetor -the idle circuit was damaged. The needle valve was completely closed. That seems like a factory placing, so there was no obvious idle circuit adjustment possibility. We have been running the motor dry of fuel each time. We have added Sta-Bil to the fuel. We also added Sea-Foam to clear anything else that might be impinging on performance. We are planning on running Avgas with Sta-Bil to see if there is a difference.

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Intriguing, as after 13 years we're amazed at how the wee (2 stroke) Tohat stands up to abuse. Sits in the boat between antifouls and rarely fails to obey.  After 10 years (and a gasket leak) we decided to treat her to a new motor (also a now rare 2 stroke 9.8). And it has performed pretty much faultlessly for 3 years. A few items that have needed attention... 3 blower fans (water getting up into the tubing), new cables from remote (getting stiff/sticky) and a fuel flow problem from an ill fitting non return valve on one end of the line from the tank.  One other thing to watch out for;  condensation will result in water in the tank so it should be fully drained occasionally. The pick up is in the bottom of the tank, note. And always use full fat fuel. The only alcohol on the boat should be strictly for human consumption.      

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Thanks. The former owner bought a 4 stroke Tohatsu in 2016. His solution was to buy a new carburetor every year since acquiring it . Several responders have mentioned the need to drain and clean the fuel tank. Most say that the Sta-Bil solution is their "best practice:".

 

Another Tiger owner mentioned he runs the motor until dry, takes his fuel tank home with him, and refills it each time.

 

For his solution, he has removed the grille on the side of the outboard well, and runs an external tank with a hose through the opening. After using it, he takes the fuel tank below. Are many of you doing that? Otherwise, how do you remove the tank without pulling the motor? 

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Drill a hole large enoug for thr fuel line fitting to pass through beside the grill in the cockpit. You can purchase a rubber plug that snaps in if you don't like it open all the time, This also works great for taking a second tank along for longer deliveries. Just plug in the new tank without worring about spilling fuel.

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On 8/30/2020 at 1:17 PM, zks7 said:

I am having some repeating problems with a 2 year old Tohatsu 9.8 motor. Are there any chronic repetitive problems with this motor?

 

I have spent about $1300 on the repairs in hte past few months for various "doagnosis". 

 

Tune up, replace impeller,

The motor is difficult to start: Replace the electric choke module and linkage

Field rebuilt the carburetor.

 

  • Motor is hard to start
  • When it starts, it runs at high revs.
  • As I back off it dies.
  • If I do get it to start, it runs well until I back off the throttle..
  • Then it dies, and will not restart.
  • The mechanic who has been out to the boat repairing it says it is a "bad motor for the environment".

 

Sounds to me like he cannot fix it wants to get out of working on it anymore...

 

 

  1. Former owner says that he did not have this problem, but he replaced the carburetor every year and everything was fine.
  2. Is anyone having this problem?
  3. Is there a solution (you have found)?
  4. Does anyone have a replacement motor they have used that will fit the footprint of the engine cavity?

 

Do you run it out of fuel every use? If not that's the problem and why the previous owner replaced the carb every year. Also these carbs are very cheap these days and the quality is pretty suspect on the cheap ones... Spend good money on a quality factory carb and don't let fuel sit in it EVER... 

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I hate those motors, but from experience you can rebuild the carb in about 20 minutes after you've done it a dozen times or so.  That was my unhappy solution.  Setting up a proper external fuel filter doubled the time between rebuilds, which meant once a year instead of twice.  Carb is about as good as the one on the base model home depot mower.    

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Thanks. The former owner bought a 4 stroke Tohatsu in 2016. His solution was to buy a new carburetor every year since acquiring it . Several responders have mentioned the need to drain and clean the fuel tank. Most say that the Sta-Bil solution is their "best practice:".

 

Another Tiger owner mentioned he runs the motor until dry, takes his fuel tank home with him, and refills it each time.

 

For his solution, he has removed the grille on the side of the outboard well, and runs an external tank with a hose through the opening. After using it, he takes the fuel tank below. Are many of you doing that? Otherwise, how do you remove the tank without pulling the motor? 

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Thanks for the replies.

I NOW run the motor dry every time we take the boat out. Thanks to your combined advice. Each time we fill the tank we add Sta-Bil and every other time I add Sea Foam to the gas. I also took the carb apart and rebuilt it. just like you said, it was pretty easy. When I tried to source the carb, the factory carb from the US distributor was around $250 at my door. The rebuild full kit was $50. I now have 1 compete and 2 partial kits to work from.

 

There was an in line water separator and filter on board prior to acquisition.

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you can usually find a package deal on 5+ kits if you want to save some money. You'll need them.

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I didn't buy a tiger, I worked on a few though. My Tohatsu 4-stroke experiences are from another boat.

those who added bobstay did so to be able to carry a tight-luffed a-sail for reaching legs or ultra-light upwind conditions. Can't get luff tension when that black dick is bending off 

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11 minutes ago, zks7 said:

THX. Where did you find the 5 pack?

Long time ago, found it through my outboard guy.  I'd guess e-bay these days

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Have you tried running Tru-Fuel through it? It doesn't have ethanol in it so it won't pull the moisture out of the atmosphere. 

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I've had the same issue with the Tohatsu. The small carburetor jet repeatedly clogged and started to need cleaning every few times we went sailing. The outboard was having other issues (not running enough cooling water through despite a new water pump, impeller and thermostat), so I decided to call it quits.

Last weekend I installed a new Yamaha 9.9.   

A few notes on this:

  • There are very few motors that will fit in the spot (the Yamaha was the only one I could find). I originally tried to order a new Tohatsu because I knew it would fit, but the dealer told me they were discontinuing it in favor of a 9.9. He couldn't get me dimensions on that one. A number of brands are moving their 9.9s to EFI which makes them taller. I don't know how long it will take for carburetors to be obsolete, but when that happens the new outboards won't fit in the well (several inches too tall)
  • We had to make a slight modification to the bracket in the FT10. The bracket was narrower than the outboard clamp, so we had to grind ~ 1/4" from the aluminum so it would fit. 
  • The Yamaha controls fit in the right spot, but we had to drill a larger hole for the electronic wire to fit

I've only run the engine once, but it was much smoother and seemed to do a great job. The model # is F9.9LEB, it cost $3700 with controls and cables.  I'm in San Diego if anyone local wants to have a look.

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Thanks US216,

I had some considerable troubles. Eventually we calmed the starting issues. It was frustrating and expensive (time).

After buying the boat (was told there was a motor issue) we took the motor to have it serviced. The options were to buy another outboard - or service this one. Had a hard time getting a solid answer about fitment. Quickly thought it was worth exploring the repair route (I was anxious to sail the boat). We took the motor off (2 people) and to an outboard shop. He did not seem to do much - but charged for his "time". He demonstrated that the motor ran. When installed on the boat, it was a different story. Many small issues kepit from running. I eventually rebuilt it (had a spare carb from the prior owner). The other carb had an idle circuit valve that was closed> That is a factory adjustment? One cannot adjust it. It is a factory pressed valve. Only reason I picked it up on it was comparing by  it with the spare carb. Then there was in issue with the electric choke. It was missing. Then there was series of days playing (with 2 people) the throttle and transmission. There also was an air leak in the fuel line connector (needed tightening). Then one day the cotter pin connector on the transmission shaft failed.  Learned a lot from all that.

 

After that time (about 2 months worth of chasing down nits), the motor went stable and started with a minimum of issues. 

 

Procedurally the advice was to add Sta-Bil to the fuel. Once a year add Sea Foam (both from O'Reilly's). Each time after running the motor pull the fuel line and run the motor until it runs dry. pull ht motor up and leave the hatch open. We have a cover so it stay open without the elements affecting the motor enclosure. The idea is to try and keep the compartment lass moist.

 

Maybe this will give you some procedural ideas about how to keep it running?

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zks7,

 

Having owned a Tiger for a few years, I too had engine issues in the beginning.  Replacing the carb fixed 99% of the m. After changing it out, every time we put the boat away for more than 1 night we ran the fuel out by simply disconnecting the fuel line and letting the engine die.  This keeps the fuel from varnishing the inside of the bowl/jets/ect while it sits.  We also used the Quicksilver fuel additive to fight off the ethanol issues. We never had any issues after doing those steps.  As far as ventilation to the engine compartment, I would  put my hand over the vent exhaust once and awhile, if there was decent airflow coming out,  you're good there.  Good luck! Fun boats. 

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