Fuel Starvation, fuel supply seems good

Force50j

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Jul 24, 2016
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I am working on a Force 50 hp. I am a auto Mechanic by trade but am slow when it comes to outboards. Just got this boat a few months ago and the previous owner said the only repairs he had to do was replace the stator. Ran fine for the first few cruises and then I took it fishing. It was at idle for a long time and I must of overheated it. I replaced the impellor as it was shot. After trying to start it I problems. The neutral throttle was not working. Then adjusted the linkages and it worked well. Took it for a few laps with no issues. Went out yesterday and after about an hour it sounded like I was out of gas so I turned it off and switched from the 6 gal tank to the 12 gallon tank. It would only idle in max throttle. If I went to put it in gear it would stall. Now I can not get it started at all. Checked the fuel filter screen and it had some junk on it but not clogged by any means, pulled the fuse line off that comes out of the pump and it seemed to be spitting fuel out (not sure if it is supposed a stream because it was not) pulled the bowl off the carb and the float was not stuck and there was fuel in it. I am going to look at it more today. Any ideas what's wrong with it? I don't work on a lot of carbs. It may be something small I am missing. Are there any other filters besides the screen?
 

Jiggz

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The engine overheated. The next logical thing to do is to test compression on all cylinders. If compression is good check for sparks on each spark plugs. If both have good sparks, and you said you got fuel in the carb bowl, try spraying fuel oil mix ( small spray bottle will do this) directly into each carb (while cranking it over, might need a 2nd person to do this) to see if will even "cough" or try to fire.

If it cough's then you know you have carburetion problem. If it still would not cough then it could be the reeds. But that is a long troubleshooting so try the above first and post your results. Also need to post the year of the motor.
 

gm280

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:welcome: Force50j to iboats, Always nice to have a new member...

I would go back to the fuel pump. Usually the fuel pump will supply a pretty good stream of fuel. And since you stated yours isn't, I would certainly look into that. The other suggestions above can be tried as well, but I think you do have a fuel delivery issue also. JMHO!
 

Force50j

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Jiggz, I knew I was over looking something. You were right, low compression (74 and 86). Pulled the head off to find out the head gasket had failed. There was water in the cylinders. There is light scoring on the top 1/2 inch of one cylinder. I think it will be fine. As i was cleaning the gasket surfaces I noticed a water, wishy-washy sound as I rotated the pistons and water coming back up the cylinder walls after they had been dried. Is there a way to drain water out of under the pistons where the crank is? I will order gaskets today but need to know nothing else is damaged.

The engine is a 91.

Thank you for the help!
 

Force50j

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Jul 24, 2016
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gm280, I was thinking that but was not sure. It may be a separate issue. I will check it out when I get it back together.

Thank you.
 

Jiggz

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You need to do an open and inspect on the crankshaft cavity and the entire cylinders. Dismount the carb and the the intake adapter. Remove the reed blocks and you should have access to the piston rod bearing caps. You will need a 12 point 1/4" socket to undo the bolts. Caution, you need to stuff the cavity between the lower cowling cavity and the engine to prevent parts falling into it. Watch out for the roller bearings and make sure you account for all.

Remove the bearing cap and roller bearings. Push out the pistons and do a thorough inspection. I recommend replacing the pistons and rings with Wiseco kit which will also require a new wrist bearing kit. If the pistons are still in perfect shape and you just need rings, you can also do the same.

Take a lot of pictures while taking it apart. You can search this forum to gain more know how on how to replace piston without taking the engine apart but only through the carb and intake access.
 

jerryjerry05

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May 7, 2008
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" Is there a way to drain water out of under the pistons where the crank is? "
​The motor is self draining and shouldn't keep water anywhere.

The exhaust chest gaskets might need to be changed too.
If it got hot enough to blow the head gasket they too could be damaged.
Be VERRRRY careful removing the screws holding the cover.
They twist off easily and can be a B to remove.
 

Force50j

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Jul 24, 2016
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Dose any one have the torque specs and rotation of the head gasket bolts on a 1991 Force 50 hp
 

Jiggz

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Oct 23, 2009
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No Title

Yours require a 225 in-lbs that is INCH-LBS which is about 18.7 FT-lbs. Double check because if the head bolts are the larger 3/8" (50 HP, 1984-1989) then the torque requirement will be 270 inch-lbs. If your motor is truly 1991 then it should have the 5/16" bolts (body diameter of the bolt and not the head size) with 225 in-lb of torque. I do not have the torque pattern but here's one use on larger motors. Typically it is a spiral pattern starting from the inside going outward.

Always make sure you do at least a two step torque process, i.e. torque all bolts to about 120 inch-lb and then come back for the final torque of 225 in-lb.
 

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Force50j

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Jul 24, 2016
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Ok I checked it all over and after letting it sit the cylinder seemed clean and water free. Bolted head back on with new gasket and tested compression (110-115). The RPMs seemed to Lil low on idle and with adjustments I could not get rpms up. Not enough to stall but low never the less. Ran fine for just over an hour then like last time seemed to run out of fuel. I seen a forum where this happen before but they never posted the final. I pulled the pick up line out of the tank and put it in water a blew in it and got air bubbles where the pick up line connects to the top of the tank plate. Now the only thing I can think of is that the oring is not maid for fuel and after an hour or so of fuel running through it shinks causing air to pass by. I am stretching for awnsers. Any input is appreciated.
 

Force50j

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Jul 24, 2016
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JERRY, I did not want to risk snapping a bolt off so I let the exhaust gasket be. I will check them this winter as summer is to short and I assume that it would only cause a external exhaust leak any way. Am I correct?
 

Jiggz

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Oct 23, 2009
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Install the clear fuel filter between the fuel pump and the carb inlet. This will at least divide the equation into two, i.e. is it a fuel delivery problem or carburetion, electrical or reed problem. Search the forum for clear fuel filter and how to use it for diagnosis.
 

Jiggz

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You're welcome and enjoy. It's really nice if all member actually comeback and post conclusion to their problems. It makes it easy for others looking for solutions to their problems.
 
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