Force 85 locks up flywheel when starting then backfires

[astinus]

Hello everyone I just got a 1985 Bayliner with a force 85. Started up with a little trouble so I let it warm up and went out at trolling speed, when I went to accelerate it shook and would only go 25 mph.

I replaced the sparkplugs thinking one cylinder was not firing.. Now it will not start at all. At first it would rumble for about 1 second then jerk the engine like a kick back. Now all it does is kick back, while the starter is spinning the flywheel it stops then starts up again and will backfire when it stops sometimes.

What I have done so far.
*Checked for spark good on all 3.
*Compression #1 134. #2 131. #3 131
*Carb kit over night soaking.
*New plugs
*Fuel line checked

I have sprayed fuel mixed in the carbs while trying to start nothing.. I have been talking to a few mechanics and I wanted to ask you guys is this could be the timing pin? I don?t want to pull off the fly wheel if that?s not what it is.

Please help I am new to boats....

 

[jerryjerry05]

Re: Force 85 locks up flywheel when starting then backfires

Sounds like you might have spun the key on the flywheel or the magnet on the flywheel has come loose.Jerry

 

[JB]

Re: Force 85 locks up flywheel when starting then backfires

Clearly a timing problem. Most likely sheared flywheel key.

 

[eurolarva]

Re: Force 85 locks up flywheel when starting then backfires

Try putting the old plugs back in and see what happens. Sounds more like you reversed the spark plug wires. Did you replace with the exact type of plugs and if so what are they?

 

[seamoors]

Re: Force 85 locks up flywheel when starting then backfires

Good Morning,

regarding sheared flywheel key; should you be able to see the key when looking down into the notch on the flywheel under the nut? I have similar symptoms to above on my '86 125 and I don't see the key in that notch. Thank you

 

[steelespike]

Re: Force 85 locks up flywheel when starting then backfires

I don't think the flywheel key will cause lock up and backfire. It retards the timing.It most likely would not fire up at all.I would suspect transposed plug wires. Perhaps severe flooding.Perhaps water getting in a cylinder.