1988 Force 125 won't rev much passed idle and uses way too much fuel

jimmio92

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Jul 27, 2016
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Hello all,

We've been beating our heads against the wall trying to get this motor running right, so I decided to join and ask here.

We originally thought it was the stator. We replaced it and it's changed nothing. We cleaned both carburetors. Both function properly. The fuel pump has no tears in the diaphragm and obviously works as it's drinking gas like crazy. Spark plugs were wet with gas when we last ran it.

It runs perfectly fine at idle and slightly above, but it won't rev higher than ~1800RPM. It acts like it wants to but then gets "stuck" at one RPM.

Any help would be greatly appreciated.

Thanks,
Jim
 

gm280

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jimmio92 :welcome: to iboats....

Two things stick out for me. First the fact that you say it goes through gas like crazy. And secondly, that the plugs are wet when you remove them. Have you checked the reeds out? If one or more are stuck open, it could be causing such issues. Or if they are bent or not closing properly. JMHO :noidea:
 

jimmio92

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Jul 27, 2016
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Have you done a spark test and Is the choke sticking?

Spark is fantastic. Plugs are brand new. Choke works correctly.



...Two things stick out for me. First the fact that you say it goes through gas like crazy. And secondly, that the plugs are wet when you remove them. Have you checked the reeds out? ...

I suspected reed problems. I bought a Force outboard Clymer manual and it shows every motor Force has made it seems including mine... except when it comes to fuel recirculation. There's no diagram that accurately shows this motor.. Am I to assume the reed(s) are in the intake behind the carbs? Like I said, the manual doesn't show it or I'd have checked it already.. I don't want to tear the whole motor to pieces if I can help it. Oh, and thanks for the welcome :)
 

Jiggz

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Maybe you need to go back to basic testing like compression test. Post your readings as soon as you get it done.
 

jimmio92

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Jul 27, 2016
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Maybe you need to go back to basic testing like compression test. Post your readings as soon as you get it done.

I will get my cylinder compression testing tool out and get exact numbers. The motor runs perfectly (low end and idle.. smooth purr) so I really doubt it's compression related, but I'll check anyway and post results.
 

jerryjerry05

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Does it spit back out of the carb? no? then the reeds are probably good.

​The valves in the pump test them and see if they are sealing right?

Clean the carbs again.
Making sure the main jet's not clogged.

Was working on a motor it had the same problem.
I cleaned the carb 3 times and finally #3 did the trick???
I never did see anything in there it just started running better.
Install a filter between the carb and the pump.
Replace all the hoses and inline connectors.
The squeezie too.
The squeezie can be bad right out of the box.

Check all the trigger connections.
Sometimes when advancing the throttle the wires move and loose contact???

Excessive fuel use? Did it ever run right?
You change the prop lately?
 

gm280

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If that fuel pump is using the crankcase vacuum/pressure pulses and is ruptured, then it can suck fuel straight into the engine bypassing the carb(s) and that could also be a cause for the situation. But you stated you already checked the fuel pump. So I would recheck the fuel pump, the carb(s) and even the reeds IF the compression checks out okay. JMHO!
 

jimmio92

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Maybe you need to go back to basic testing like compression test. Post your readings as soon as you get it done.
Compression tested. All cylinders within 2PSI of each other, roughly 140PSI. (Old dial gauge isn't that reliable. Took reading 4 times per cylinder and got ~140)

Does it spit back out of the carb? no? then the reeds are probably good.

​The valves in the pump test them and see if they are sealing right?

Clean the carbs again.
Making sure the main jet's not clogged.

Was working on a motor it had the same problem.
I cleaned the carb 3 times and finally #3 did the trick???
I never did see anything in there it just started running better.
Install a filter between the carb and the pump.
Replace all the hoses and inline connectors.
The squeezie too.
The squeezie can be bad right out of the box.

Check all the trigger connections.
Sometimes when advancing the throttle the wires move and loose contact???

Excessive fuel use? Did it ever run right?
You change the prop lately?
It doesn't spit fuel out the carburetors as far as I can tell.
The "valves"? Are you saying there's more to the fuel pump than the diaphragm? Are there check balls or something in it that may have somehow failed?
I will clean the carburetors again today (if I have any more carb cleaner..) but probably won't get a chance to try it out today.
There is a filter there already. It was there when we bought the boat.
Replace all the hoses seems unnecessary.. unless there's a blockage. If there was a blockage, it wouldn't use so much fuel I'd think, but I will replace them anyway.
The squeezie (primer bulb?) was just replaced with a brand new one as the old had dry rotted. They can be bad out of the box? They consist of two one way valves and a bulb, right?
The trigger wires were tight last I checked, but again, I will check them. That sounds like a very plausible cause right there.
It never ran right since we bought it.
We have never replaced the prop. It's in good condition, though.

If that fuel pump is using the crankcase vacuum/pressure pulses and is ruptured, then it can suck fuel straight into the engine bypassing the carb(s) and that could also be a cause for the situation. But you stated you already checked the fuel pump. So I would recheck the fuel pump, the carb(s) and even the reeds IF the compression checks out okay. JMHO!
I'll probably just replace the fuel pump diaphragm as the gasket behind it is hard and seems brittle.. probably means it's old and needs replacing. I'll recheck the fuel pump, reclean the carbs, and pull the intake apart and check the reeds.

Thank you all for your help so far. :)
 
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gm280

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Post what you find so we know what caused your problem(s). It will also help others with similar situations as well. After all that is what these forums are all about, helping boaters.
 

Jiggz

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If not yet installed, install a clear fuel filter (Fram G2 for less than $5 will work) between the fuel pump outlet and the carbs inlet. Orient it so it is slightly on the vertical and closer to the fuel pump outlet. Next, check make sure the butterflies or throttles in each carb goes to horizontal with the control lever in full forward position. Do not confuse the choke butterflies for the throttles (located far inside the throat of the carb)

Prime it to fill the clear fuel filter at least half full if not more. And do a test run at the lake with the cowling off so you can monitor the status of the clear fuel filter. Obviously, you will need a second person to drive while you check the filter.

If the filter stays at least half full then you know it is a carburetion, reed, timing or electrical problem if the engine would not rev past 1800 rpm.
If the filter empties, there is a fuel delivery problem start looking for bubbles in the clear filter. If there are bubbles, then there is an air leak upstream of the filter. Check hoses, primer bulbs checkvalves, and quick disconnects.
 

Derrick Fronckowiak

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Jul 15, 2015
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If you eliminate the fuel problem and your original discrepancy hasn't gone away, just to ENSURE you get a good spark on ALL cylinders ALL the time (at idle or throttled up) wiggle each terminal on the ignition chassis on the terminal bar. Wiggle each one (while the motor is running) right where each wire attaches to each terminal. See if it affects firing either at idle or throttled up. I just had two intermittent open wire terminals on my #2 pack that only seemed to make and break connection when I throttled up (high vibes???) or flexed the terminals. It's easy to check and if you are in doubt it is simple enough (not to mention a whole lot cheaper) to replace and resolder any terminal before moving on to buy expensive ignition components (like I foolishly did BEFORE checking the terminals).
 

jimmio92

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Thank you all for your responses, they helped me immensely by ruling out what couldn't cause it. I'm absolutely sure I've found the problem, finally..

Are you all ready for how stupid the problem was? I cannot believe I missed it when I cleaned the carbs.. (then again, I "assisted" my step-father-in-law (who owns the boat) in cleaning them, that's probably why I missed it.)

The top carburetor has a high speed jet. The bottom DOESN'T HAVE ONE. :facepalm::embarassed: So.. it's getting probably triple or more the amount of fuel that it needs. No wonder it was burning so much fuel! No wonder the plugs stayed wet! So now all I have to do is identify the jet in the top, get one for the bottom, and it'll be boating time!

The left side of the jet has a large 2 stamped in it. The right side has two digits vertically stamped, the top saying 0 I think (it's pretty tough to read), and the bottom says 8. .208? Does that sound even remotely correct? Attached a photo of the jet (8MP camera, cropped) so maybe someone can read it better than me.

Thanks to all that chimed in,
Jim
 

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jerryjerry05

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The jets are: .080 .090 .092 / .101 is standard at sea level to 1500ft. for top carb.
​.0937 standard at sea level to 1500ft.
The lower #s are for higher elevation.
Can't make out what yours says.
Maybe a piece of steel wool?
They have 2 different size jets.
Maybe someone here has their jets written down someplace?

​Yes there are 2 valves in the pump.

The primer has 1 one way valve.

​By chance? is this the original boat/motor combo?
Yu can send the hull# to the maker and they would have the model and serial#(easier to get parts)
 
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gm280

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If you have some quality drill bits, you can take them and see which ones fit that opening (using the shank end). I have a very inclusive set of drill bits and the increments are very fine. So I can use them to measure such things and then take a vernier caliber and see what size it actually is. That could help to get the exact jet size you need. Just an idea.
 

jimmio92

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Does anyone know where I can get a jet for this carb? I've called local boat shops and no one seems to carry a .0937/.094..
 

gm280

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Does anyone know where I can get a jet for this carb? I've called local boat shops and no one seems to carry a .0937/.094..

Is there any boat salvage yards around you? If so there is a pretty good chance there is a motor there you could buy it from. Maybe the whole carb and then you'd have a back up. If you could buy a jet of smaller size, you could drill it out or have it drilled out. And if worst comes to worst, check a machine shop to have one made. Check the internet for all the engine part places as well. There are always ways. JMHO!
 

jimmio92

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Jul 27, 2016
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Is there any boat salvage yards around you? If so there is a pretty good chance there is a motor there you could buy it from. Maybe the whole carb and then you'd have a back up. If you could buy a jet of smaller size, you could drill it out or have it drilled out. And if worst comes to worst, check a machine shop to have one made. Check the internet for all the engine part places as well. There are always ways. JMHO!

We called around and there was none.. or none that would part with just the jet. They want about a hundred for a carburetor that we'll never use.

We went ahead and ordered an exact replacement from boats dot net, but it's seventeen-ten-thousandths smaller (.0017" smaller; .092") than stock because actual stock jet is "obsolete". It's for 1500ft above sea level to 3000ft. Our lake is ~750ft above.. so I imagine it won't be TOO lean.. but then again, we have the tools to drill it out to the stock size. The real question then becomes...

If the stock top carb jet size is .101, why is the jet labeled with the numbers 2 on the left, and 3 8 stacked (.238?!)? That seems like an awfully big difference between .101..
 

gm280

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We called around and there was none.. or none that would part with just the jet. They want about a hundred for a carburetor that we'll never use.

We went ahead and ordered an exact replacement from boats dot net, but it's seventeen-ten-thousandths smaller (.0017" smaller; .092") than stock because actual stock jet is "obsolete". It's for 1500ft above sea level to 3000ft. Our lake is ~750ft above.. so I imagine it won't be TOO lean.. but then again, we have the tools to drill it out to the stock size. The real question then becomes...

If the stock top carb jet size is .101, why is the jet labeled with the numbers 2 on the left, and 3 8 stacked (.238?!)? That seems like an awfully big difference between .101..

jim, have you actually measured all those jets? Some times the markings are not an actual jet size opening. It could be a marking that crosses over to the true size on some chart somewhere. :noidea: However, take the shank ends of the drill bits and actually measure the jet sizes to know for certain their sizes. May find they are not all different. JMHO!
 
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