Spark Advance timing screw not working.

[johnm]

The screw that controls the timing spark advance doesn't appear to be working. Motor is a 55HP Env. 79' model. Turning the screw clockwise or anitclockwise does nothing to the timing. Using a strobe light indicates that there is no movement whatsoever. After re-cleaning my carbs, I hadn't checked the timing BEFORE going out, but timing was ok before carb clean. Yesterday the engine was at it's worst it's ever been, in fact I got towed in because it eventually died after cranking it about 60-70 times. I decided to check the timing when I got back home and it was out by about 3 degrees. Now I can't adjust it. It was a bad day...

 

[papasage]

Re: Spark Advance timing screw not working.

john i have a 55 1979 i cant se how cleaning the carbs would effect the timing your carbs may not be sincornized. i went out last weekin mine wsa serging like it was not giting enough gass. found ahose hung up on a bolt when i let the motor down .did it stop at bhigh speed or idling?

 

[johnm]

Re: Spark Advance timing screw not working.

It woud stop at idling. It started ok the first 6 or 7 times, then when put in idle it would conk out, even with idle screw up dangerously high. After that it wouldn't start at all. My timing is out 3 degrees regardless. Do you know why my timing screw isn't having an effect on my timing?

 

[Solittle]

Re: Spark Advance timing screw not working.

John - Being off by 3 degrees will not cause the symptoms that you are describing. Check your manual and do a sync & link to the carbs & follow that with the timing check. If that does not do it you will probably need to rebuild (not just clean) the carbs.

 

[Mufasa]

Re: Spark Advance timing screw not working.

I would take a quik look at the spark plugs and compression, pull the head if low compression is indicated and inspect. The timing is controlled by the movement of the timer base under the flywheel. The screw you are adjusting is for wide open throttle (WOT) and you would need to time that at about 4,500 rpms to get an accurate reading. I suspect it was not against the stopper and not effecting the timing at all at the speed you checked it at. Are you sure the trouble is in the carbs?

 

[johnm]

Re: Spark Advance timing screw not working.

The carbs have been rebuilt twice. The motor idled fine before the 2nd rebuild(when cold, has trouble when warm). I've probably screwed something up when putting carbs back together, but don't know what. Engine is a dog even when cold now too. I've done a lync and sync, what else could it be? A few weeks back I posted another topic about my motor stalling and lots of info has been provided. ie compression, spark tests etc and I think I got close, but I must have done something wrong while putting the carbs back together this time. My fuel is 3 weeks old. Could that be the problem?

 

[Hooty]

Re: Spark Advance timing screw not working.

JohnM,<br />I'm probably not understanding what you're saying but the timing screw doesn't change the timing. It's just the stop for the timer base.<br /><br />c/6<br /><br />Hooty