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1995 Force 120 hp has no power in the top end

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Cheyney2334

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I currently am expierencing issues with the top end after chasing my tail for a month.. first it wouldn't stay idling so I replaced all the fuel lines still no fix after some research and cleaning and checking the carbs making sure the needle seats are clear and the bowls weren't sticky I moved to spark found only 3 cylinders were firing so I swapped wires around and plugs still no spark so I swapped coils still no spark in cylinder 4 so I replaced the power pack and boom I had spark and it starts everytime I turn the key but now I've suffered a bad WOT loss. The engine idles fine in the water and gets the boat on plane slowly but after that she won't push the boat over 24mph.. could this be a bad stator or rectifier? Or a timing issue.. it ran fine before all of this and compression is awesome for a engine of its age!
 
What's the compression on each cyl?
Double check the spark on each cyl?

Any backfiring? Any cough, stutter at low speeds?
Any blowback from the front of the carbs?
Miss at higher speeds?
 
Cylinder 1 - 125 Cylinder 2- 123 Cylinder 3- 115 Cylinder 4 121 taken with mediocre gauge. I will double check spark and get back to you. Been a slight sounds like a pressure release when trying to start which I assume was a back fire but usually fires right up after that. Possible miss at high speeds shakes a tad and sounds horrible.
Edit after checking some fuel coming out of carbs
 
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If you don't have a pulse tester to check your trigger another way to check it is just change your firing order around the no sparking plug will then just move to another cylinder then you know for sure your trigger is faulty.
 
The backfire,cough, stutter can all be signs of the intake sucking air someplace????
Do the starting fluid test.
On hose or DEEEEP in a bucket, start motor and spray starting fluid around the intake side,
including under the coils,power pack etc. A quick shot in the carb can make it stall, stutter etc.
If the sf makes a change? then find where it's sucking air??
The carbs tight? Gaskets good?
Ethanol screws up the older hoses and the crud it releases from the hoses clogs the carb.

Fuel from the front of the carb? That could be the reeds gone/going??

u-tube: look up Force outboard static timing, carb setup.
Send me a PM with your email and I'll send you things I can't post here.

Comp 125 123 115 121
The 115 is a bit low but that can be because that cyl runs the fuel pump. Rebuild the pump.
If it's bad the excess fuel can effect the comp and the way the motor runs at ALL speeds.
With good equipment it should be 145-165 The important thing is all 4 should be 5-8# of each other.
The 94-99 the top and bottom can vary as much as 10-15# difference than the 2 center holes.(whacko engineering)
Send that email.
​
 
I will pick up some sf today and submerge it in a bucket and see what the outcome is.
I am unsure if the gaskets are good or bad we rebuilt the fuel pump after we did the compression it was leaking and we thought that was the problem.
We also replaced the gasket for the plate that attaches to the block behind the pump.
While checking for a vacuum leak i will recheck spark feel free to email me anything will help! [email protected]
 
DEEEEP in the bucket, has to be 4-5 inches over the cavitation plate.
The pump only works if it's been submerged over the blades of the impeller.
Not self priming.
 
If it goes bad#3 cyl. it feeds excess gas into the cyl and cleans walls and carbon off the rings.
Doesn't affect it much.
Comp on #3 was 5-10# different than the other cyl.
Just something to look for?????
 
Force from 1991 to 1996 is Mercury designed ignition system .Timing at idle between 2 degrees BTDC and 4 degrees ATDC , WOT is between 20 and 22 degrees.
 
Seems as if my issue is a lack of fuel the bulb is going soft at high Rpms and not at low rpms. Took it out to the lake today and did some tests will be pulling fuel lines and checking for minor blockages if I don't find any I will move up from there any clues on where to start other than fuel hose and possible a shot pump again?
 
Going soft is OK!!
Collapsing isn't.
The only thing the ball does is draw the fuel from the tank, then when the system(carbs,pump,etc) is full it gets firm.
Then it just sets there and allows fuel to draw past until you need it again.

Collapse, then there's a tank vent issue, possibly wasp, bees, bugs etc.making nests or a pinched vent hose.
 
Still hitting a brick wall did some tuning on the carbs and it helped bring it up a couple mph but I found that I potentially have a bad float on the bottom carb when squeezing the bulb fuel come right on out the carb.. potentially all of this is now turned into a carb issue. Also looking at replacing the reeds but they are expensive I would prefer it to be a last ditch resort.
By the time this is over there won't be an old part on this force 😂
 
Only replace the reeds if they are damaged.
If there's a gap in them as they set there?? Normal
Unless it a huge gap.

The float, what kind? Pic??

You sure the needle's OK? Smooth tip? rubber tip or solid? Pic?

Solid tip needle.Look down inside the seat, you should see a rubber seal,
sometimes they get dislodged and leak sometimes spray cleaner and soaks eat the rubber seal??
 
Not sure haven't had a chance to dig into it been busy lately. However what doesn't make much sense to me is the fact that before I replaced the cdi I could run almost 40mph on choppy water but she idled really rough and had a hard time starting. Now that I've replaced it she idles like a dream but won't run over 25 mph on flat calm conditions. It does good right up until I'm about to get on pad and when that happens the tone changes and sounds terrible shutters and surges.�� as soon as I get the time I will pull the carbs apart and check the needle and the float. Will also post pics.
 
If the ignition part works at slow speeds????
Then it should work at higher speeds.
Unless the timing arm or linkage is broken?
 
Well sadly I'm back to ask more questions. Lol I rebuilt the carbs and thoroughly cleaned them and replaced the floats to no avail. Stopped the fuel leaking out of the mouth of the carbs but still surging on top end replaced the fuel filter and primer bulb just to be sure. However I've learned that the cdi module that was replaced was a cheapy could that still be my issue?
 
He stopped asking questions 3 years ago.
If you have a problem?? open your own thread.
Ask a question and include any and all info that might help???
 
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