1989 Force 85 hp seems to miss

[bradleeson]

Yes more at wot, but in other areas of the throttle as well. Does not seem to shut down, just miss and jump a little. This is the first time I have had this motor out and I just installed it on my boat. So I know my throttle is not yet adjusted correctly, which I have read on here can cause problems, but I don't think it is consistent with my problem? I am just wanting some suggestions on what to first check?

Thanks...

P.S. Starts and idles really well.

**P.S.S The plugs all looked good.

 

[roscoe]

Re: 1989 Force 85 hp seems to miss

Could be as simple as old gas, or water in the gas.

 

[jerryjerry05]

Re: 1989 Force 85 hp seems to miss

Like Roscoe said water possibly.Install a water/fuel seperating filter.It can make a lot of difference.J

 

[bradleeson]

Re: 1989 Force 85 hp seems to miss

It has fresh gas that also has 1 OZ of "procleen" by quicksilver in it. Even though the gas is fresh should I install the separator?

*Plus does anyone Know the part number for it here on iboats? I would order way more off here if they would just put what part goes to what year!

 

[bradleeson]

Re: 1989 Force 85 hp seems to miss

Did find a bolt that fell off of the top right of the manifold. maybe causing an air leak?

 

[pnwboat]

Re: 1989 Force 85 hp seems to miss

If there was an air leak I would think that it would affect engine operation at all speeds, especially at idle where the manifold vacuum is high.

Do the basic checks first. Check compression. I doubt this is an issue but it may give you some idea as to what shape the cylinders and rings are in. I always do this before purchasing an engine, marine or automotive.

Check plugs, change if necessary. Verify plug wires and or boots are not arching (this can be a shocking experience if you know what I mean).

Replace the fuel pump diaphragm. Cheap and easy to do.

Make sure all the ground wires on the coils and the block are making good contact. There is a ground wire that goes from the plate the coils are mounted on to the block. Make sure all the screw connections on the ignition terminal block are tight.

When you're working with a used engine like this, it's best to just start from scratch and eliminate one area at a time. Eliminate the basic easy things first. I guess the biggest problem is deciding where to start, but thats the joy of boating!

 

[bradleeson]

Re: 1989 Force 85 hp seems to miss

Hey pnwboat, check this link:

http://forums.iboats.com/showthread.php?t=298900

 

[pnwboat]

Re: 1989 Force 85 hp seems to miss

Well certainly looks like you've got all the compression issues covered. Also noticed that you checked out the plugs. Sorry I missed that. My apologies. The other issues regarding general checks (grounds, plug wires etc.) still apply.