Flywheel timing marks

[tjello327]

Hello forum,
I have a 1986 125hp Force. It backfires when I try to start it when its cold so I re-checked how to set the timing and found that I did it wrong. This is the way I set it first, I started the engine & let it idle, set my flywheel zero mark right on with the timing tab mark. After reading my book, I found that this is wrong. It says to put the boat control in forward gear & at full throttle, have someone crank the engine over (dont let it start) and set the static timing to a maximum of 34 degrees BTC. Well I have 3 marks on my flywheel that are not marked so I am not sure which one is right. There is a formula in my book on how to lay out an unmarked flywheel and when I applied this formula to my flywheel, it comes out to the furthest mark from the zero mark should be the right one. The problem with this is that I guessed that the closest mark to zero was the right one and it started right up with no backfire. I then read into it further and found that by using the formula, I was on the wrong mark so I re-set to the furthest mark and it backfired. Could have been alot of fuel in the cylinders from all the cranking over i guess. Anyone know which mark is 34 degrees???

Thanks,

 

[tjello327]

Re: Flywheel timing marks

I just check an older post on this issue and found my answer (I think.) It said that the markings from left to right looking at the flywheel are 32 degrees, 30 degrees & 28 degrees (28 is closest to TDC mark.) It then stated that a 1986 125 hp engine should be set to 28 degree BTDC. This is where I had it set & it seemed pretty good. My piece of sh*t Selco manual said to set it at 32 degrees BTDC. It backfired set there. I think I am setting it back to 28 degrees. Anyone have any ideas?

Thanks,
Tom

 

[chitownborn]

Re: Flywheel timing marks

i timed mine to 28 degrees static timing, which would give you 30 degrees at wot that was the sweet spot on mine static timing is really easy to do disconnect all plug wires and ground them use jumper wires to do so,ground them to block somewhere, bypass your neutral switch, advance your throttle to wot, hook up timing light to no 1 cylinder, crank engine and set timing to 28, when all done and put back together youll be at 30 good luck don

 

[tjello327]

Re: Flywheel timing marks

I moved it back to 28 degrees. Hope this thing gains a little more RPM.

Thanks!