Help someone must also have vibration on 9.8 tohatsu

[rocket rich]

i JUST GOT THIS MOTOR ON SEPT 13TH AND USED IT YESTERDAY FOLLOWING BREAK IN METHODS. AT LESS THEN FULL SPEED IT VIBERATES. Will this go away with use??

 

[pvanv]

Re: Help someone must also have vibration on 9.8 tohatsu

What kind of boat is it installed on? Did the dealer do a PDI on it? Is it firing on both cylinders, or is there a bad plug?
The 2-cylinder motors are a lot smoother than the 1-cylinders. I notice a little "loping" of the powerhead down near idle on my 9.8A3, but that's to be expected, and is absorbed by the upper motor mounts.

 

[stormmnv]

Re: Help someone must also have vibration on 9.8 tohatsu

I had a 9.8 Nissan (same motor) that also ran rough. I removed the brass plug to the idle control needle and richened it up a bit and it smoothed out and idled fine.
My dealer said that they lean them out to meet emmision specs. Then put plug over the adjustment screw so we cant mess with them.

 

[rocket rich]

Re: Help someone must also have vibration on 9.8 tohatsu

well , my motor is running very nice since Paul (St Paul) put me on the right path. All is well , but thanks for the imput..

 

[pvanv]

Re: Help someone must also have vibration on 9.8 tohatsu

I had a 9.8 Nissan (same motor) that also ran rough. I removed the brass plug to the idle control needle and richened it up a bit and it smoothed out and idled fine.
My dealer said that they lean them out to meet emmision specs. Then put plug over the adjustment screw so we cant mess with them.

Your dealer was mistaken. Yes, the plug is there because of the EPA, but the mixture is set by instrument at the factory. Obviously, it is possible for it to have been set too lean at the factory, but I have seldom if ever seen that. Truth is, very few mechanics know how to set that jet correctly, and even fewer "shadetree" mechanics have the precision tachometer and hearing (and patience) to set it correctly.

A more likely scenario: If and When the carb needs to be cleaned, some lazy mechanics will instead richen the pilot jet to cover up the varnishing (idle) problem -- instead of doing a proper carb cleaning. But, should the carb ever be cleaned correctly after that, then the pilot is too rich, and will both use more gas, and foul plugs at slow speeds... and of course it will be out of emission specs. BTW, it is a violation of Federal law to make that adjustment. Not that I've ever heard of the EPA-police making any arrests.

 

[Sea Rider]

Re: Help someone must also have vibration on 9.8 tohatsu

RR,

You are probably using your engine with ther tiller steering friction pad adjusted too light, with engine off move tiller side to side, if you don't feel a resistance while doing so you have a light adjustment. Adust with proper tool the nut located sideways on middle stering body and adjust it CC untill you feel a mediun hard resistance. A good adjustnment is the one in which you can release the tiller and engine stays running on a straight course, adjust nut CC untill this condition is met.

Happy Boating