Carb trouble

Alabamed

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Apr 21, 2013
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Have a 1991 Force 50hp, are there other year carbs that can be used on this motor or do you have to match the same numbers stamped on carb?
 

kbh121956

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The carb is very simple to rebuild. unless it's super messed up, I'd take it apart and clean it. If you are careful, you won't even need a carb kit. Use a Carb cleaner spray with the nozzle. Don't use brake cleaner.
 

Alabamed

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I appreciate the come back, and I've got a new needle valve ordered. Will try that first, just looking for info for a backup plan. The problem is the motor is getting way too much fuel and causing flooding, the needle valve would seem to be the culprit, unless you may have a better idea
 

jerryjerry05

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May 7, 2008
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They used the same carb.on a BUNCH of different motors.

Look up on boatsdottnet parts diagrams.
It tells you what it fits on.

The seat might be the problem??
There can be 2 different setups.
One has a needle with a rubber tip.
The other has a solid tip and a rubber seal in the seat.
Inspect the seat and needle for damage.
Some soaks/cleaners destroy the rubber in the seat.
 

Alabamed

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Apr 21, 2013
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Well I installed a new needle valve, old one did look to have a slight groove on one side, but did not make any difference. The only other thing that seems possible to me is the float. So I ordered a new float, and I don't see how old one could have gotten out of adjustment, cause ran okay a few months ago. Must not be floating properly, any other ideas?
 

jerryjerry05

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Model or serial# ??
Check the fuel pump.
The diaphragm might be bad?
The float should be level when carb is turned upside down.
The float "drop" should almost touch the center post when turn right side up.

You have the old style choke? or the enricher system for choke?
The enricher has a rubber diaphragm that can go bad.
 

Alabamed

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Apr 21, 2013
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Well I have old style choke, and is working properly. I believe if diaphragm was bad on pump it would not be getting enough fuel, I have the opposite problem, too much fuel and flooding. Float seems to be set properly, so I'm thinking the float is faulty and not closing needle all the way.
 

Jiggz

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Oct 23, 2009
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When you say, flooding do you mean like fuel mix is pouring out of the carb's mouth even with the motor in full vertical position? With the motor off, when you press on the primer bulb does it get firm? If it does not and if you continue to press it and fuel mix starts pouring out of the carb mouth or opening, then it is absolutely either a float or needle valve problem.

How about the idle mixture, is it set at 1 turn out from slightly seated? Have you inspect the needle for smoothness?

When motor is running at idle, do you see fuel pouring out of the carb opening, either spraying or running out? This can be a float or needle valve problem but also a reed problem.

Need to hear more symptoms to properly diagnose.
 

jerryjerry05

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If the diaphragm is bad it will feed extra fuel direct into the system.

Does the ball pump up firm and go soft after starting.

Like Jiggz asked: more info?
 

Alabamed

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Apr 21, 2013
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Well I wasn't aware the diaphragm being bad could cause extra fuel direct into system. The ball seems to be fairly firm then goes much softer after starting. Nothing spraying out of front of carb, just the motor getting too much to burn it all, had to turn idle control almost closed to get it to idle at all
 

kbh121956

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Jun 30, 2013
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Pull the carb and re-clean it. Double check that all small holes are clear. While holding the carb outside down with the float level, can you blow any air through it using the fitting where the fuel line hooks up? You don't want to run it with the needle valve being almost closed, you want it somewhere around one turn out when lightly seated. While you have the carb removed, take a look at the reeds. Don't rush through when cleaning the carb, take your time. Post your results, Jerry and Jiggz will also chime in.
 

Jiggz

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Oct 23, 2009
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The fuel diaphragm works by flexing in relation to the differential pressure in the crankcase cavity caused by the up and down motion of the piston.

If there is a slight tear in the fuel diaphragm it will start leaking fuel into the crankcase cavity eventually getting pushed in into the cylinder. This results in a very rich mixture in one of the cylinders where the fuel pump is located.

Depending on the severity of the tear, the engine could continue to run albeit at a richer fuel mixture state. This can also affect engine performance but for sure higher fuel consumption.
 

Alabamed

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Apr 21, 2013
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What you say makes good sense to me on the fuel pump, so ordered parts to rebuild.
 

Jiggz

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I wish you did an open and inspect first, although it's never a bad idea to have a spare fuel diaphragm.
 

Alabamed

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Apr 21, 2013
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Just figured as old as it is I might as well replace anyway , but I feel that this is probably my problem. Only thing that really makes sense with my problem
 

Alabamed

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Apr 21, 2013
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Just writing to thank you for info on fuel pump, was indeed the problem and had a rather large crack, rebuilt and back up and running. Thanks again
 
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