85 hp Force keeps fowling plugs

[boatox]

It has had this problem since I bought it three years ago. I have rebuilt the carbs with new needle and seat, new floats and new gaskets. Has new inline fuel filters, new coils, all new fuel lines. I have about twenty hours on it since all of the work I have done to it. Last trip I took it out was about 25 minutes each way. One month later I take it out, after ten minutes it started missing. Idles fine but dies when given any throttle. Happened once before and new plugs cured the issue. I have the manufacturers suggested plugs in it. Just curious as to why they might keep fowling? Should I use a different plug? Am I running it too rich?

 

[jerryjerry05]

Re: 85 hp Force keeps fowling plugs

Cheap oil,too much oil,excessive idling.Carbs air screw set at 1 turn out.RPM around 750.
You don't say the year so I'm guessing 84-89 They need a UL-18V Perma-gap plug.Good thing about those plugs the can be cleaned with a wire brush and re-used forever. J

 

[boatox]

Re: 85 hp Force keeps fouling plugs

Re: 85 hp Force keeps fouling plugs

It is an 88. Did not think of the oil. I will keep an eye on that. Although I avoid the cheap stuff when I can. I will reset my air screw to 1 turn out. You say excessive idling, but I always have to start and let it idle for a couple minutes before giving it power. If I don't it stalls.

I have been using the NGK BUHX plugs I get them from West Marine. They are pretty much the same as the 18V's I think??

No way of checking rpm.

I will clean my plugs with a wire brush today and see if it works.

Thanks
Jon

 

[Dave K.]

Re: 85 hp Force keeps fowling plugs

surface gap plugs carbon up quickly! i use the same ngk plug & clean them a few times a season & i don't use the boat as much now as i used to but still have to clean the plugs

+1 on what jerry said.

 

[Jeremy90bay]

Re: 85 hp Force keeps fowling plugs

If im correct you should be warming the engine up in the high Idle position, not just sitting in neutral. Correct me if im wrong anyone.

 

[boatox]

Re: 85 hp Force keeps fowling plugs

My controls only allow me to warm up in neutral. I dont have any throttle only controls. Its on an 88 bayliner.

 

[pnwboat]

Re: 85 hp Force keeps fowling plugs

You also want to check your fuel recirculation system. If it's not functioning properly, you may experience fouled plugs. There are some check valves and sometimes some filter screens that get plugged up with old fuel residue and debris that can affect it's operation.

 

[foodfisher]

Re: 85 hp Force keeps fowling plugs

The control handle should hve a release mechanism to free you up for fast idle. On my '86, you pull the whole handle away from the hull towards the middle of the boat. Some have buttons to push or triggers to pull.

 

[john from md]

Re: 85 hp Force keeps fowling plugs

If you don't have a button to push on your trottle quadrant, then your trottle handle will pull inward to release to push forward for fast idle.

These engines are cold blooded and need more warmup than newer engines but this does not cause them to carbon up enough to shut off. If your plugs are fouling often, I would suspect the fuel recirulation system is clogged up.

If you look in either the Seloc or Clymer manuals, they will show you where the recirc orifices are. They need to be blown out with carb cleaner or taken out and cleaned. Also, the recirculation reed valves may be sticking. This requires removing the side panel on the engine and cleaning the reeds.

John

 

[Jeremy90bay]

Re: 85 hp Force keeps fowling plugs

I have a 1990 bayliner and I have to pull the control out away from the hull also. check it out You have to have some sort of way to high idle.

 

[boatox]

Re: 85 hp Force keeps fowling plugs

Awesome feedback, thanks everyone. I am working on it now so I will check for idle control and I will go through the fuel recirc system. I have the Seloc manual so I will be using that.

Thanks again. Will update later with whatever I find.

 

[boatox]

Re: 85 hp Force keeps fowling plugs

Checked the fuel recirc system. Did not find anything there. Only had two hoses and three valves, all looked fine. I would not call them valves yet elbows screwing into the enigne. Sound right? Took off fuel pump cleaned it out as well. Nothing really struck me as being clogged or out of the ordinary. Clean off my plugs started it up, adjusted my idle a little bit. Seems to be fine now. Just wondering if it will foul out again.

Oh and thanks, now I now how to fast idle. My control arm was the kind that pulls out, never knew it.

John from MD - you said this
Also, the recirculation reed valves may be sticking. This requires removing the side panel on the engine and cleaning the reeds.

Not sure where to find that my manual did not really get into that.

 

[john from md]

Re: 85 hp Force keeps fowling plugs

On the 85hp engine, the elbow under the carbs is a fine orifice. It gets clogged easily because of tilting the engine and causing fuel to come out. The fuel evaporates, the oil congeals and the lower cylinders run rich.

The side plate is on the right side of the engine in front of the coils. It is about an inch or so wide and runs vertically. It has three reeds in it that get gummed up and stick.

Regards,

John

 

[boatox]

Re: 85 hp Force keeps fowling plugs

OK- mine kind of looks like a dog bone. I should take that whole plate off and clean it all out?

 

[john from md]

Re: 85 hp Force keeps fowling plugs

Yes but be careful of the reeds as you just want to clean them and not distort them. If you are careful, you can reuse the existing gaskets.

John

 

[boatox]

Re: 85 hp Force keeps fowling plugs

OK did that. Didnt look too bad in there. Took all the reeds off and cleaned them. I guess it is just a matter of time to see if any of this helped. Thanks for all of your help John.

 

[john from md]

Re: 85 hp Force keeps fowling plugs

Many idle issues can be traced back to carb/timing syncronization. Because of the mechanical timing, the carbs have to be set just right or it doesn't work.

Have a great summer.

John

 

[Dave K.]

Re: 85 hp Force keeps fowling plugs

+1 to everything stated above...lots of solid info!

Yes, ck the plugs somewhat often & clean them as needed. w/ mine, once i hear some hesitation when starting, it's mostly carbon build up & time to clean.

glad you figured out the fast idle..certainly will fire faster

 

[boatox]

Re: 85 hp Force keeps fowling plugs

After I took out the reeds and cleaned them it wont stay running. I think I might have an electrical problem. Not sure. Does not seem like the bottom cylinder is firing. Gonna attack it today.