Setting timing and idle on muffs.

[butlp]

Following the directions in my manual, I tried to set the timing on my 1988 Yamaha 90 hp.<br />I set the linkages to the approximate positions and then started the motor on the muffs. No matter how I tried I could not get the timing to match up with the specs. (I think it's 5 deg. BTDC, don't have the manual with me).<br />Timing light was on #1 cylinder and motor fired right up, running fine.<br /><br />How much difference does it make running the motor on muffs verses in the lake? Should I just wait until I put the boat in the water and check both idle and timing then?<br /><br />Thanks,<br />Peter

 

[JB]

Re: Setting timing and idle on muffs.

Howdy, Peter.<br /><br />Doesn't Yamaha specify that those settings are made with the engine under load?<br /><br />I can see setting idle without a load, but timing is a function of throttle setting and running throttle up without a load on the engine is an invitation to disaster.<br /><br />Double check your manual. Good luck.

 

[butlp]

Re: Setting timing and idle on muffs.

JB<br />The manual says to set the timing at idle and then under load at above 2500 rpm. It does not state that the idle setting should be under load but as it's all in the same section it maybe assumes you are.<br /><br />I have read all the threads on this board about de-carboning and tuning and thought I would give the motor a thorough check before the season begins. As it was trying to snow last week in Ontario I opted not to put the boat in the water and in doing so, did a half hearted job. I'm returning to the lake mid June and hopefully summer will have arrived in Canada and I can complete the tune-up.