Electronic fuel pump.

[karayj]

So last year I was having problems and I think I narrowed it down to the fuel pump. I heard a lot of these just last year or two on the cheaper brands. So I figured I’d get an electronic fuel pump. So what I did was I set it up with an oil pressure switch one to the relay on the left side and one on the relay to the right side. The way this works is when you turn the key the first phase start so it gives you something to get fuel going. And the second wire going to the other oil pressure switch connector is while the boat is running. The beauty of this is if there’s no oil pressure, the pump turns off Water. My problem is the voltage seems to be too small not enough to really get some good pumping action going into the carburetor. When I do a direct connection from the battery, it’s too much and it floods to that carburetor. Now my other question is when I do it directly to the battery and it’s a 4 to 6 PCI electronic fuel pump. Is that normal for something like that to flood the carburetor. I may go back to old school mechanical fuel pump but I just don’t trust them.

 

[karayj]

So last year I was having problems and I think I narrowed it down to the fuel pump. I heard a lot of these just last year or two on the cheaper brands. So I figured I’d get an electronic fuel pump. So what I did was I set it up with an oil pressure switch one to the relay on the left side and one on the relay to the right side. The way this works is when you turn the key the first phase start so it gives you something to get fuel going. And the second wire going to the other oil pressure switch connector is while the boat is running. The beauty of this is if there’s no oil pressure, the pump turns off . My problem is the voltage seems to be too small not enough to really get some good pumping action going into the carburetor. When I do a direct connection from the battery, it’s too much and it floods to that carburetor. Now my other question is when I do it directly to the battery and it’s a 4 to 6 PCI electronic fuel pump. Is that normal for something like that to flood the carburetor. I may go back to old school mechanical fuel pump but I just don’t trust them.

 

[Bondo]

So what I did was I set it up with an oil pressure switch one to the relay on the left side and one on the relay to the right side.

Ayuh,..... Not sure what that means, but yes, carbs are fed with 4 to 6 psi,....

 

[dubs283]

The beauty of this is if there’s no oil pressure, the pump turns off

Mercury engineering implemented this system many years ago. Pretty well known among folks here and in the marine repair field

So last year I was having problems and I think I narrowed it down to the fuel pump................. I may go back to old school mechanical fuel pump but I just don’t trust them.

Unless you have proof of failure of a mechanical pump there's no reason to replace it or even abate the system. There are many styles of mechanical fuel pumps still available today that work great, even for marine engines

You just need to be sure and obtain the correct pump for your application

 

[flashback]

QC on the electric pumps seems a problem. So check the pressure..

 

[Scott Danforth]

Mechanical fuel pumps usually last decades and cost less than 50.

Electric fuel pumps cost more and fail every few years

 

[karayj]

So I will reply as per message / I did do the oil pressure thing the problem is the rely has 2 large and 2 small connectors/ I choose the small one an dthe voltage is on 6 v to 7 volts not and the pump is 12. When I do a direct connect to the battery it pumps strong and fill the carb. On the smaller relay connects it is very weak not enough to push fuel. I tested it in a wine bottle and the flow was a joke. The other issue is the I cannot find other places that have key on and key off power. The Alternator has power but it is always on (does not seem right ) battery drainer. The left side of the relay LARGE side left is always on with key off (NOT RIGHT ) .

Why am i doing this? I bought a fuel pump 2 seasons ago that seems to be sucking in air . Somewhere air is getting in I feel. I also running with clear fuel lines so I can see bubbles this time when I am on the lake I want to see if it's an air in the line issue causing low power issues.
Last year the boat ran great for 45 seconds then stuck at idle to stop it form stalling but when throttled up it would die and take 15 min to get it start and then I have to idle back to the ramp . You can rev it fine but under a load it will die. I check the clamps for air leaks and found none so I am buying a new pump 40.00 as a back up . I want to be able to power around this summer and not idle around

 

[karayj]

I want to add to the post above rather than edit it I’ll just put it here. Is it normal and I really don’t think it is for a boat to have constant power going to the starter relay with the key not in the ignition and is it normal for an alternator. They have power going to it with the key not in the ignition. There’s a red wire in the back that feeds all the systems. It just doesn’t seem right. I’m thinking somethings wrong with the ignition end that whoever did the wiring before I bought this boat screwed up .

 

[todhunter]

Yes, it is normal for the alternator and starter to have 12V at them even with the key off. I'm not sure what engine you're working with, but on my 1987 Mercruiser V8, the starter battery is connected directly to the starter (well...there is a battery shut-off switch between them), and the alternator (orange wire) is fed directly off the starter. These should not be drawing loads with the key off / engine off. If you are concerned about this, you can add a battery switch.

 

[karayj]

Yes, it is normal for the alternator and starter to have 12V at them even with the key off. I'm not sure what engine you're working with, but on my 1987 Mercruiser V8, the starter battery is connected directly to the starter (well...there is a battery shut-off switch between them), and the alternator (orange wire) is fed directly off the starter. These should not be drawing loads with the key off / engine off. If you are concerned about this, you can add a battery switch.

That’s exactly what I did. I had a battery switch. Thank you very much.