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1976 Ford 302 OMC Fuel Pump Circuitry Problem (Breaker?)

J

jawoodruff

New member
Hello,

I have almost no experience on auto and marine engines.

Recently I was left with the task of repairing an OMC Ford 302 190hp engine. Currently I have gotten the engine to run, but I had to switch a few wires around to do so and that causes undesirable behavior.

The fuel pump is supposed to kick on when the starter is engaged (correct?) and is supposed to remain running when the ignition switch is released and is allowed to return to the 'on' position (assuming the switch's turn from left to right is off, on, start with 'start' being the position that kicks back to the 'on' position when released).

The problem is, that with the factory wiring, the fuel pump never starts despite the engine turning over. However, I can change a few wires to make the fuel pump run in the 'start' position of the ignition switch only and the 'on' position only. But, this is not correct because if the ignition switch is turned to 'on' the fuel pump runs even if the engine isn't going to be ran.

I had to replace the starter solenoid and before then, the fuel pump ran properly with the default wiring. I'm guessing I threw a breaker or blew a fuse somewhere along the way and I don't know exactly what to look for or where it is. Of course, it might not be a fuse or breaker (all fuses I found looked fine). However, I don't know where the breakers are located.

The service manual I have doesn't have a complete wiring diagram for the engine.

What would cause the fuel pump to not engage? The fuel pump does in fact work because I can run the engine with modified wiring, but as I said, it has adverse side-effects.

If something was unclear, I'll be happy to clarify.

Thank you,
Jared
 
I would think the pump should stop after the presure is up to where it should be. 12 - 15 lbs ??? Just my though
 
What carb you got on that old piece of iron ?

76' motor did not have a electric fuel pump. Maybe someone added one latter.

Did they use a 7 max psi pump? Do a psi test on the pump first !

You got a manual stay away from claymor get a seloc #3400 right hand corner.
 
Chief is right - not factory equipped with e-fuel-pump.

Current philosophy says to get an oil pressure controlled SPDT switch. Common lug feeds the pump, NC lug goes to starter circuit, NO lug goes to ignition circuit. Provides b+ during cranking and while engine is running, provided it has oil pressure.

Andrew has the switch if you need it - look at the top of the page under engine parts..
 
Ok then, what would cause the pump to lose pressure while the engine is running?

Edit:

The carb is a Holley and the fuel pump is from a company called Carter
 
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are you talking about the fuel pump? .....usually lack of B+ causes the pump to stop running and the fuel pressure drops real quick. Sometimes, the internals fail, like in any other electric motor.

I'd be inclined to make sure the wiring is 'current' and that all components are functioning.
 
fuel pump not giving fuel smack it on the side with a hammer like a cheating wife.

Just kidding tap it on the side with the base of the handle.
 
The fuel pump works properly. Current is supplied during engine start and fuel is pumped into the carb.

Chief is right, it isn't an electrical fuel pump. I believe that somewhere after the pump and in the carb there is a pressure leak. Perhaps the carb needs a rebuild? It's been sitting a while and some gaskets could have a leak, causing a vacuum to be impossible.

Is this a plausible cause for a lack of proper pressure in the fuel line? Would a carb rebuild and clean possibly fix the problem?

P.S. - The service manual did confirm that the fuel pump is not electric and that the fuel is supplied via a vacuum created by the fuel pump and carb.

Thanks,
Jared
 
While I'm not much of a Holley Carb fan, you might be able to get it going again by taking the thing apart and giving it a good clean out. There are rebuild kits available from our host which should refresh the lump to the point that you can get some use out of it. If you don't have a compressor to provide air to blow out the passages, go to Radio Shack or the like and buy some canned air. You can't do a rebuild without blowing the dirt out of the little passages. Get the big can of soak type carb cleaner from your local auto parts store. It usually comes in a gallon can with a dip basket included.
My 2 cent guess is that the carb has sat so long that the gas dried out. This can cause the needle valve to stick which will ruin your whole day. There may also be resinous goo in the bottom of the float chamber. While you are doing the rebuild, replace all the supply hose from tank to carb with good Shields Flex-acol fuel hose.
Personally, my next step would be to order the Edelbrock Marine Performer 1409 carb from Jegs. They have the best price. When you consider a rebuild, even a DIY job, the difference between that and a new carb isn't all that much (in boating dollars). It arrives in a box, you bolt it on, hook it up and away you go. Badda Bing.
 
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jawoodruff said:
The fuel pump works properly. Current is supplied during engine start and fuel is pumped into the carb.

Chief is right, it isn't an electrical fuel pump.
P.S. - The service manual did confirm that the fuel pump is not electric and that the fuel is supplied via a vacuum created by the fuel pump and carb.

Thanks,
Jared
Click to expand...


OK....so I'm confused all to hell, does this thing have an electric fuel pump or not??? First you talk about rewiring to make the pump run and breakers and now you say it isn't an electrical pump?????????????????????????/ Do you know what you are working on as people try and give answers based on the information you give them!!!
 
My first post is incorrect, I made the mistake of assuming it was an electric fuel pump, it is not.

It has been mentioned a few times already that it is not an electric fuel pump.

So, here it is again: The fuel pump is not electric, I thought it was.

This project was dumped on me and I wasn't told a damn thing about it so I'm not 100% familiar with it.

Now that we all know the fuel pump is not electric, would a bad gasket in the carb cause the fuel line to lose its proper vacuum?

Would a carb rebuild fix a potential pressure leak?
 
o2batsea said:
While I'm not much of a Holley Carb fan, you might be able to get it going again by taking the thing apart and giving it a good clean out. There are rebuild kits available from our host which should refresh the lump to the point that you can get some use out of it. If you don't have a compressor to provide air to blow out the passages, go to Radio Shack or the like and buy some canned air. You can't do a rebuild without blowing the dirt out of the little passages. Get the big can of soak type carb cleaner from your local auto parts store. It usually comes in a gallon can with a dip basket included.
My 2 cent guess is that the carb has sat so long that the gas dried out. This can cause the needle valve to stick which will ruin your whole day. There may also be resinous goo in the bottom of the float chamber. While you are doing the rebuild, replace all the supply hose from tank to carb with good Shields Flex-acol fuel hose.
Personally, my next step would be to order the Edelbrock Marine Performer 1409 carb from Jegs. They have the best price. When you consider a rebuild, even a DIY job, the difference between that and a new carb isn't all that much (in boating dollars). It arrives in a box, you bolt it on, hook it up and away you go. Badda Bing.
Click to expand...

Thank you for reading all the posts and keeping track of updated info.

I wish I could say I had more money to put into this thing but I'm fixing it to sell it because I need the money. I'll work on rebuilding the carb and replacing what I can. I'm almost completely positive it's a pressure problem.

Thank you.
 
Oh.

Well just sell it. Let the next owner sort out the carb. You probably aren't going to get hundreds more with a carb rebuild. Far more important that it be clean and not appear shabby. Clean the hull, make it shine, get all the dirt and stains out of the interior. Make sure everything is spiffy. That will get you more money.

Tell the prospective buyer that it will run with a new carb, as it surely will.
 
o2batsea said:
Oh.

Well just sell it. Let the next owner sort out the carb. You probably aren't going to get hundreds more with a carb rebuild. Far more important that it be clean and not appear shabby. Clean the hull, make it shine, get all the dirt and stains out of the interior. Make sure everything is spiffy. That will get you more money.

Tell the prospective buyer that it will run with a new carb, as it surely will.
Click to expand...

I'll just do that then. I would love to be able to keep the boat, but I just can't.
 
>I'll just do that then. I would love to be able to keep the boat, but I just can't.

One thing is for sure: the boat you are meant to have will find YOU. You cannot find IT.
 
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