85 force bog down question.

[mick97]

My force is on a bayliner and it seems when I have 4 people on it,it doesnt get up and plane as good or as fast.
With just me its fine.

All summer I have had to kick it full throttle to get it up to the point I can plane out.
Then when I let off the gas just a tad,it speeds up even faster.Which is what I want is faster,,,but then it slowly starts throttling out.

So I just take it down to the putt putt level and run it for awhile.
After 10-15 minutes of that speed,i can push it and get it up to plane again.

As long as i have it full throttle,its fine....Mabe a tad slower than it should be,but runs good.

If I just putt along for 3 minutes or so and then try to go full throttle,it bogs out.But waiting and running it for 10-15 minutes,then shes ready to take off again.

Weird.

i did open the jets to 1 1/4 turn earlier this summer.

Do you think its mabe flodding a tad?These motors all smell a little anyways,and I don't detect any stronger odor at all.

I don't have a timming light,but i road timed it to get it to the point where it finally would plane out,earlier this summer,so i just settled for that.

Could it be the timming that would cause this?

Or any others have a similar problem like this?
New prop,new gas diaphram,new plugs.
No problem with air in the tank,or cloggs.

Any ideas would be appreciated.
Thanks,
Scotty

 

[Frank Acampora]

Re: 85 force bog down question.

Well, Scotty, I think you may have multiple problems. One: you may have a weak fuel pump and replacing the diaphragm is in order. Never mind! I didn't see that you had already done that.

Two: It is possible that your carbs are opening too far and need to be adjusted. Search out, read, and follow instructions in my recent post "Synchronizing carbs and timing."

Three: depending upon the boat size, four people will load down an engine that size. The smaller the boat, the more she will be affected by extra weight. And, the correct prop is necessary. Sometimes you need to change. Case in point: Alone or with one person, my 21 foot cuddy with a Chrysler 140 uses a 19 pitch prop. 4 or more persons, or water skiing and I change to a 17 pitch.

 

[mick97]

Re: 85 force bog down question.

Thanks I will check out your posting on that.

Ya,its a 16 foor bayliner.
So you think prop too mabe hu?

I replaced it with the same one that was on it when I bought it.
Bought this spring and it ran good for the other guy I guess before I bought it.

I cant remember what pitch it was.Will have to re-look into that.But it looks like you went down 2 sizes for when your skiing hu?

So from 19 to 17 is a smaller prop correct?
Not too keep on these prop pitches.

Thanks,
Scotty

 

[mick97]

Re: 85 force bog down question.

The prop I bought was a 13x19.
So 19 inch I guess.
Scotty

 

[jerryjerry05]

Re: 85 force bog down question.

Basics.Compression test.Spark test.Then fuel system.
Ethanol is messing up a lot of motors.J

 

[Frank Acampora]

Re: 85 force bog down question.

As a guess, I would say that a 19 pitch prop might be too much. It is difficult to say without data. You really need a tachometer and need to see what the full throttle RPM are now. It should be between 4500 and 5500, preferably toward the upper end.

If RPM is at, say about 4800 or lower, then a decrease in pitch to 17 will give about 400 RPM more bringing the engine into its best power range

 

[mick97]

Re: 85 force bog down question.

well,a little late in the season this year,but I think I will buy a 17 prop.The more power the better
Thanks all for the help.
Scotty

 

[cairngorms]

Re: 85 force bog down question.

I have a force 85hp and if you read my recent response to Jerry, i cured the the problem of bogging down and Frank has some great stuff on this. My motor now runs great with 5 up and no probs planing even with a 19 inch prop. good luck!!

 

[mick97]

Re: 85 force bog down question.

Kewl,

Looked for the thread but couldn't find it.
Scotty