Newbie Problem/New Tohatsu 9.8 motor

[TOHATSU GURU]

Re: Newbie Problem/New Tohatsu 9.8 motor

"If there was something wrong with the carb, such as varnished passages, then it came from the factory that way. I have videos of the first start and the thing running poorly from the get go. The poster above had similar issues and a shop performed the procedure for him with success."

Yes and no. The engines are test run at the factory. More than once I have seen a new engine with some residual fuel left in the carb. I have also seen a variety of metal shavings, rubber and plastic in a new carb....That's why new engines have a warranty. But, screwing around with the air mixture screw is 100% not the way to correct the problem. Cleaning the carburetor or even replacing the carburetor(under warranty) is the correct method. Tweaking the air mixture screw, even if it does temporarily mask the actual problem, is only a short term or bumpkin fix. You or I can't argue with success, but "success" should be measured as solution without an unnecessary penalty. In this type of case that penalty is the wasting of fuel, violation of federal law and the voiding of warranty. Of course, the Feds will never do anything, Tohatsu will almost certainly still honor the warranty and the amount of fuel wasted is slight. I'm just a strong believer in correcting the problem rather than masking it.

 

[5thwheeler]

Re: Newbie Problem/New Tohatsu 9.8 motor

I finally got around to adjusting my 9.9 last weekend (about to be at coast for a week). I tried what tohatsu guru said with the idle adjustment screw and it did not improve my idle quality much. The engine still idled poorly and shook around bad.

I did fix it however, by screwing out the brass plug and adjusting the idle mixture screw. 2 and 1/8 turns out along with slight adjustment of the idle speed screw yielded great results. The engine sounds mellower out the exhaust and idles smoother.

These engines (sold for use in California) are altitude sensitive and all the carb cleaning in the world won't change that.

My engine ran great at sea level, but it wouldn't idle at 6500 ft. without the choke pulled half out. Increasing the idle speed was dangerous and bad for the engine. The nearest dealer was about 100 miles away down winding mountain roads, so I had to fight this problem for over four months.

When I came home I took engine to my dealer. He did a routine maintenance, including cleaning the carb and the engine ran fine. He drilled out the plug so I could make the needed adjustments at 6500ft.

Problem solved!

 

[TOHATSU GURU]

Re: Newbie Problem/New Tohatsu 9.8 motor

Or, instead of butchering the carburetor....Putting in the high altitude jets would have keep the engine from drowning in fuel. Again, under no condition should the air mixture screw be tampered with. It is moronic to insist otherwise.

 

[pvanv]

Re: Newbie Problem/New Tohatsu 9.8 motor

Or, instead of butchering the carburetor....Putting in the high altitude jets would have keep the engine from drowning in fuel. Again, under no condition should the air mixture screw be tampered with. It is moronic to insist otherwise.

Yes. I have got to agree 100% with Elvin. How on earth would mal-adjusting the pilot screw affect the main jet? Answer: It wouldn't. So... butchering the carb might make it idle better, but would still result in fuel-drowning under power when at high altitude. So... the end result of that Frankenstein experiment is a carb that is too lean to idle properly at sea level, and is also too rich under power at high altitude. In other words, a piece of junk.