85hp Force - 1989 - WOT Bogging

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Sep 10, 2020
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85hp Force - 1989 - Model # - 856X9G - WOT Bogging

Issue is, will run great at WOT for 20 seconds then descend bog up an down, finally settling down to 1/3 speed, full throttle.

Will do fine at idle, under low speed and 1/3 speed.

After the WOT bog down, will not perform same trick to get up to full speed for at least a few minutes or not at all.

Shut engine down, let sit for a few moments. Start again. Can perform the same trick, with same behavior dependently.


Acting like a fuel issue. Feels like a flooding issue. Again. Not sure.


Does seem to idle kind of high though. Need to figure how to measure RPMS with tachometer. ( would favor a permanent tach install or just easy tool, Either. )

Checked fuel lines - seem adequate fuel in inline filter before carb.
( Water separator used after tank )

Changed Plugs & Boots. NOT Cables or Power packs ( packs appear replaced )



When carb tuning - Adjusted Idle Carbs to 1 turn out, does well there.

Air / Fuel mixture screws ( not sure if correct ) on face of carbs are set completely in when i got it. Ran fine but had bogging issues when engaging low gear
.
General Owners manual says set 1 turn out, doesn't make a lick of difference. There's also no needle parts of the screw.. Just brass mixture screws. I believe. Still not sure.

Carb butterfly flaps and link rods appears correct.



Still haven't found a very specific shop manual or the best of best shop manual for this engine. Feel like it could clue me in better.

.
 

topgun3690

Ensign
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May 7, 2019
Messages
970
Sounds like fuel starvation. Mine did the same, turned out to be the fuel pump diaphragm. Could also be a bad squeeze ball or internally delaminated fuel line, or maybe a plugged up tank vent.
 
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Curious. Prime bulb goes sporadically from rock hard and strong pumps - quickly filling the inline fuel filter - to nearly no pressure and pushing air. Engine off, idling, WOT. indifferent.. Real flaky. Been trying to trace it back with no avail.

Should pressure build up to fuel pump or before carbs at some point? Don't understand the process or whats normal.

Fuel pump spits fuel good when I got the out-line to carb. hose pulled off, though maybe not enough for sustained WOT

Had similar issues before sporadically. Now has recurred and become a dependable issue. Replaced all fuel lines and it seemed to increase the frequency that the prime bulb stays hard and inline filters stay full.

Is it necessary bulb stays hard and inline's stay full? - Off / idling / WOT ?

I have two of them in line after the water separator to view whats going on. One after prime bulb. One after fuel pump / before carbs.

Is there a good way to test fuel pump? pressure gauge or tricks?

I need to figure out the ways of diagnosing this issue and my entire engine in general.

Would love a top shelf shop manual ( echo, echo )


Thanks ineffably
 

topgun3690

Ensign
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If you haven't replaced the pump diaphragm in a year or 2 or not sure when or if it had been changed at all, it may be time to do it. The ethanol fuel is bad for the rubber, makes it stiff and rigid. I change mine every couple years just like the impeller. The squeezie ball stays hard until fuel starts flowing, the inside can delaminate like the fuel lines and plug up. Next time you replace the squeezie cut open the old one and take a look inside.
 

topgun3690

Ensign
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May 7, 2019
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970
A Factory shop manual is what you want, Clymer and Seloc not so much, less detail. Check ebay they ususally can be found there.
 

topgun3690

Ensign
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May 7, 2019
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Be sure to check back early in the morning....the Force gurus will chime in with more detailed analysis of your issues.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
The squeezie: it's only job is to draw fuel
from the tank and fill the bowls and get firm.
Then it does nothing.
After the motor starts, the ball can go somewhat
soft.
2 in line, could be causing a problem if one's bad?

Try running with the cover off the motor.

Check the tank vent line, wasps and other bugs get
in the line and can block it.

Compression test, spark check each cyl.#2 runs the
fuel pump.

Rebuild the fuel pump.

Remove the foam from the cowl/cover.
 
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Sep 10, 2020
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Spent all night re routing the fuel lines, re-thread taped old fittings and consolidated the lines. Prime bulb has a much better feel. Pulled the fuel fitting on the tank and noticed the stem cracked.

Running the engine at night, I can see arcing happening from the rubber spark plug wires making contact with the block. Orange spark. Sometimes happens at the base of the plug as well as where the wire connects to its corresponding spark pack.

On nearly every unproductive carb adjustment attempt or over priming during fuel testing - #2 carb, is always the one to flood, heavily.


Few more hours till light and I can take it on another test run,

( Gaining some real hope, thanks to this forum, kudos )
 
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Sep 10, 2020
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Fuel Tank pickup stem - Not 100% if was broken before my removal. Felt like so. Fuel Gauge needle seems pretty jumpy and inconsistent either way ( assume that's a different gauge anyway )
 

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Joined
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Test Runs no different, lines seem air tight seems though.

I can see fuel in the 2nd inline filter after fuel pump staying about 1/4 full. Seems enough but not sure.

2nd carb. always floods heavily when it's idle screw is adjusted towards lean.


Air / Mixture screws on top of open face are set all the way in. That's how it was before from P.O. 2nd carb idle was set only 1/4 turn out from seat. That's before lines were changed and had its own list of issues.

Owners Man says set those air / mix screws ( they are not needles ) 1 turn out to start with and adjust. Then adjust idle screws.

Can't notice a difference between air / mix screws being seated or 1 out. May just be naive or confused.
 

topgun3690

Ensign
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May 7, 2019
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10. I can NOT stress this enough! NEVER set the low speed needles less that 3/4 turns out no matter how poor the idle or acceleration. To do so will run the engine too lean and detonation and melted pistons at or near full throttle operation will result.

This is from the sticky on link and sinc, Frank A.
 

topgun3690

Ensign
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May 7, 2019
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970
Did you check/replace the pump diaphragm? If its bad it doesn't matter what else you do until thats working right.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,428
With the air/fuel mixture screws all way in it would not even start. Fuel is going to the cylinders but not through
Do as topgun says, check the fuel pump diaphragm.
Fuel is getting to the cylinders some way but not through the carbs.
Spray starting fluid around the carbs flanges and intake port covers when running at idle.
If change in RPM;s then you have a leakage.
BTW Have you clean the carbs?
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,241
Running the engine at night, I can see arcing happening from the rubber spark plug wires making contact with the block. Orange spark. Sometimes happens at the base of the plug as well as where the wire connects to its corresponding spark pack.

You can apply Di-electric grease (not really a grease,more like a gel) to the boot & cables, by rubbing/massaging in the grease; This special grease was made to protect from corrosion/conducting electricity.

Do NOT use WD40 ( or anything else for that matter) because the all CONDUCT electricity
 
Last edited:

jerryjerry05

Supreme Mariner
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May 7, 2008
Messages
17,923
They make Liquid Electric Tape.
That along with shrink tube can block some of the JUMPING spark.
 
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Sep 10, 2020
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Pulled apart the carburetors one more time and found a small piece of plastic in the inline which I removed. That made a big difference!

Now middle #2 Carb keeps flooding - fuel pouring out of overflow.

Maybe Float adjustment needed? Needle Rebuild?

Tried adjusting the float height a bit without much luck. Can't seem to get it dialed in correctly with the idle and low speeds + #2 carb. flooding is a major issue.

Doh! - out the frying pan & into the fire..


As far as Idle Mixture screws go - they don't stay put unless are seated all the way in but I agree, manual says start at 1 turn out.
 

Redbarron%%

Chief Petty Officer
Joined
Dec 7, 2017
Messages
479
Do they have the little springs on them? Plus you might have some of that trash holding the float valve open as well.
It sounds lie the inner liner of the fuel line has come loose, which is common.
Perhaps new fuel lines when you get it running.
Pull the carbs and clean them thoroughly. While you have that #2 off if you can blow through the fuel inlet with the carb held upside down the valve is not closing. Perhaps the rubber has a crack in it or some other damage.
Check each carb the same way. Also blow out all of the passages with compressed air.
 
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Sep 10, 2020
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They didn't have the little springs on them! Received a new rebuild kit but I believe the mixture screw is incorrect ( too large ). Did include the springs which may fit. Sounds like this all checks out with the current issues. Thanks a million to everyone, what a great support site!
 
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