89' 85hp force high end misfire

[ponchos_ta]

I've owned an 1989 17' bayliner capri for a year now and I still have one bug to work out of it. The engine fires right up, and idles fine. The boat will jump up on plain quickly, but at higher rpms you hear and feel a misfire every 15 or so seconds. We have replaced the fuel pump, reeds, water pump, and lower seals. People around here say it could be the stator, but I think it runs too good otherwise to be that or the cdi boxes. Last week we noticed the magnet that should be bonded to the flywheel wasn't bonded anymore. Could this be the problem? We bonded the magnet back in place, but I havent tested it yet because I'm getting my stainless props hub replaced. With the stock aluminum prop I can do 33+ in waves, with the 19 pitch stainless it will do way over 40.

 

[pnwboat]

Re: 89' 85hp force high end misfire

Helps if you note the year and horsepower of the motor. Assuming it to is a 1989 model which has the "strip" magnet. If the magnet was stuck to the stator and not moving with the flywheel, yes it will affect the ignition spark. This is what generates both the charging voltage for the battery and the voltage to the CD Modules that fire the coils. Only way to tell if this is the cause for your intermittent high speed miss is to take it out and test.

 

[ponchos_ta]

Re: 89' 85hp force high end misfire

Well the loose magnet didn't fix the problem. I have decided this is not a miss, but a skip from the lower unit. We had it apart before but the dogs didn't look in that bad of shape. I had five people on it yesterday, and it didn't skip as often as last year. Is it just as simple as flip flopping the dogs if thats all that's wrong with it?