1989 force 85 horse , idle problems.

Mike77z

Cadet
Joined
May 18, 2011
Messages
6
Hi Folks been lurking around here for a while and have a few questions about a boat and motor i just purchased.


I just bought a 1989 Maxum 17.5 foot bowrider with a force 85 horse on it, it runs fine( after some fighting with it this weekend) at high idle in neutral but the rpm is low 1000 - 1200 so it appears i have to adjust the low speed idle.

I did the normal checks before posting compression is 120 116 119 , fuel feed is fine flows good appears to have about 5 psi of pressure at 1k rpm. Carbs were rebuild and floats set on the weekend sync'd carbs , It runs fine if i just slam it to netural and then jump on the throttle however manuvering around the marina is very challenging , and i don't want to take the risk of damaging other people boats so i wont take the boat out again till i get this done.

I ordered a manual but its going to take two weeks to get here they tell me ( which sucks ) I'm a automotive and heavy truck mechanic so doing the work is not a issue its just knowing exactly what the force specs are.

Doing a little research with the search button it appears i need 30 deg timing at WOT cranking with the coils grounded and im shooting for 1k rpm in neutral at idle and 750 rpm under load. Am i correct on these ?

Anything else im missing ?

Thanks in advance Mike
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,183
Re: 1989 force 85 horse , idle problems.

In gear at idle and warm.750-800 rpm.
In the drive way it will be about 1200rpm.Air screws out about 1 and 1/8th turn.
Make sure the diaphram is good(replace it anyway)about $7.
Make sure there is no water in the gas.
Look for the linc and sinc thread at the top of the Force section.J
 

Mike77z

Cadet
Joined
May 18, 2011
Messages
6
Re: 1989 force 85 horse , idle problems.

Thanks Jerry will do , and will keep ya posted on progress


Mike
 
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