1997 s150txrv prop shake vs octane??

[K9mattk]

been trying to figure out why my 150 hp yamaha shakes so bad with a heavy stainless prop. carbs have been gone through, sink & link done but still shakes at idle in gear. Have allways used non-eth. prem gas. seems like there is unburnd gas in water running at dock. plugs allways kind of wet also. Do you think that 87 oct fuel could help reduce prop rattle. Got manual for motor, compression ratio is 6.2 to 1 that seems low to me.

 

[robert graham]

Re: 1997 s150txrv prop shake vs octane??

Maybe check for bad fuel pump diaphragm sucking raw gas into cylinders causing very rich/wet plugs condition? Good Luck!

 

[JB]

Re: 1997 s150txrv prop shake vs octane??

Going to 87 regular will not affect the vibration, but it will help your wallet. Check that stator and throttle both move smoothly and in synch. My guess is that you are dropping one or more cylinders at idle. . .one carb leaning out?

 

[Ldavidgrover]

Re: 1997 s150txrv prop shake vs octane??

In gear or out of gear? Check for bent propshaft