89 85 hp Force O/B....stumbles

[tfbrown1270]

I read all I could here and have decarbed, changed the impellor, chenaged the fuel pump and filter.etc etc.......however the motor runs poorly..........it starts OK but upon application of throttle "usually" but not always runs like its on two cylinders...then like a switch being thrown...zoom.lots of power...then just as fast back to two cyclinders...sometimes its 2, 3, 2, 3....it feels like a bucking bronco......when its running good (on 3) I have tried experimented by hitting the choke button (push in key) and the engine balks hard, instant failure, the moment I let go of the choke it comes back to life...so I don't think its lean.....from the reading I have done I suspect a power pack (they are blue).......NOW WHAT?.....I am a two stroke dunce...any help to understand the problem and get this moptor running right would be appreciated.....Thanks...Tim (Winnipeg Canada)

 

[tfbrown1270]

Re: 89 85 hp Force O/B....stumbles

Oh.and the compression is 130 on all...I replaced the exhasu manifold gaskets and head gasket already too.it has new plugs as well....just trying to cover the obvious things I see posted...thanks again..

 

[tfbrown1270]

Re: 89 85 hp Force O/B....stumbles

No thoughts!:'(....not even a "unbolt it and drop it in the lake"?

 

[tfbrown1270]

Re: 89 85 hp Force O/B....stumbles

I guess "stumbles" is a misnomer.....In fact it never stmbles, as though firing unevenly, ...it "surges"...as though running on two cylinders and then bursts of three (cylinders).....I had hoped to hear how to diagnose the problem (electrical I suspect0 and repair it at a reasonable cost....If anyone can help please let me know...If not then it will be listed on E-Bay in a few weeks as parts....thanks

 

[Kajun38]

Re: 89 85 hp Force O/B....stumbles

well you can buy 2 power packs from ebay brand new for $100 for both and see if that fixes your problem.....if not...i'd like to buy your lower unit if you part it out

 

[eurolarva]

Re: 89 85 hp Force O/B....stumbles

Ignition systems are a tough area here. If you dont hear an answer here soon you can try the marine doctor. here is a link
http://www.themarinedoctor.com/cgi-bin/YaBB.pl/YaBB.pl

 

[buddyle]

Re: 89 85 hp Force O/B....stumbles

hi,
you could try and test each cylinder if the motor running on each one or you can swap the power pack to find out which one is bad.....i had very similar problem last couple months ago.....but i got my fixed. With most of the help from numerous of expert here, you will get your motor fix....i am not one of them, just lucky that happened to me before, so i know how to fix mine. want more detail, email me....buddyle2002@hotmail.com...good luck.

 

[Matthew A.]

Re: 89 85 hp Force O/B....stumbles

Currently, my 88 85 hp force is doing the very same thing you describe. However, I don't believe mine is a powerpack issue. I've had powerpacks go bad on this motor twice. Each time the motor simply dragged one cylinder and did not show any signs of stumbling. Although, it could very well be a failing powerpack, stumbling could also be caused by a stuck float on one of the carbs. Another culprit could be an air leak in the fuel supply line. Air leaks in the fuel line can cause one or more or all carbs "usually the top carb" to deprived of fuel just enough to make the motor stumble. Another possible culprit worth looking into is a loose connection at the rectifier, faulty rectifier. Broken or loose wires at either of the wiring harness blocks. The trigger assembly wires being such small guage wire can sometimes break under the heat shrink tubing where the wire is attached to the terminal connector where the wires connect to the harness block . Causing an interminent connection. Hope this helps

 

[jasonbailey]

Re: 89 85 hp Force O/B....stumbles

Check the fuel line connectors. It maybe getting air into the the fuel lines. My o/b did the same thing, the o-ring in the female connector was bad.

 

[tfbrown1270]

Re: 89 85 hp Force O/B....stumbles

I'm going to the lake Sat...I'll give all those suggestions a shot and report back...thanks

 

[roscoe]

Re: 89 85 hp Force O/B....stumbles

I would have to agree on it being a fuel issue.
I would check all lines for cracks, and the o-ring as mentioned.
Then go to rebuilding the carbs.
Every time it surges means that cylinder is not getting fuel/lubrication.