Fuel Pump Install 305 merc

[flatiron14]

I think I need to put a new fuel pump on my '92 Regal, 305 Merc with Alpha one. I had it in the shop earlier this year and the mechanic (certified merc mechanic) mounted this electric fuel pump on the partition next to my motor. My repair manual tells me my motor is supposed to have a mechanical fuel pump that's powered off the camshaft? The electric fuel pump that's on it kinda surges a bit at idle and the motor bogs a bit when you throttle hard under load, I assume because this fuel pump can't keep up. Should I go ahead and put a mechanical fuel pump on it? Ya'll have any tips for the install?
Thanks!
-James

 

[dan t.]

Re: Fuel Pump Install 305 merc

electric should work as long as the pressure is 4-6 lb, now for the $6000000 question,is the pump wired thru an oil pressure switch as is required by law? if not it must be for your own and your passengers safety. or install a mechanical, what happened to the original?

 

[Bondo]

Re: Fuel Pump Install 305 merc

The electric fuel pump that's on it kinda surges a bit at idle and the motor bogs a bit when you throttle hard under load,

Ayuh,... Those are Carb issues...

 

[flatiron14]

Re: Fuel Pump Install 305 merc

Well, I bought the boat with some kind of crappy electric fuel pump that was way too small and the mechanic put a bigger electric one on. No idea what happened to the original. So if it should be wired into the oil pressure switch, that should regulate it some?

As for the surging issues, he fastened this pump fairly high on the partition by the motor and I know that fuel pumps pump up better than they can draw up, and since I ran it for a while like that, I think I burned up the pump. To make it start, sometimes you have to hit it a little with a wrench to get it flowing (so obviously it needs replacing ). So, in conclusion, could the crappy pump be an issue and not the carb?

Also, if I install a mechanical pump, what extra parts will I need to buy to get it to attach to the camshaft?

 

[dan t.]

Re: Fuel Pump Install 305 merc

an oil pressure switch is a saftey item, the electrical circuit passes thru the switch so that the pump will only run if the engine has oil pressure, it gets power while cranking thru a relay triggered by the starter motor circuit. it is posibly on there because your motor is not machined for a mechanical pump, most 87 and newer were not equiped for a mechanical pump because they came with elecronic fuel injection, if the mounting boss is there you will need the pump,the mounting plate and the bolts. also a STEEL fuel line, good luck

 

[Showtime22]

Re: Fuel Pump Install 305 merc

If you are worried about the pump - Go buy a new electric universal pump from Napa 45 bux. 4-6 psi. I have one works great. My mechanical fuel pump shaft was stuck and I couldn't install a new mechanical pump.

However it could be a carb issue. But by you tapping it sounds like your pump.

 

[flatiron14]

Re: Fuel Pump Install 305 merc

Well my motor is not fuel injected and my repair manual mentions little about an electric fuel pump on my motor. It indicates that it likely originally used a mechanical fuel pump. I also checked and on the starboard of the motor in the front is what looks like a bracket that could have held a mechanical fuel pump. I'm fine with doing either, I just want the right pump this time.

I also attatched a picture of the current fuel pump on it.

 

[abj87]

Re: Fuel Pump Install 305 merc

That looks like a pretty poor setup. A mechanic did this???

Switch back to the mechanical pump. no oil pressure switches no extra wiring and no failure prone cheep electric fuel pump.

 

[Bondo]

Re: Fuel Pump Install 305 merc

Ayuh,... I've got no problem with the pump chosen,...
But,...
The installation is pretty sloppy...
And,...
That clear filter is pretty Useless....

 

[soaringhiggy]

Re: Fuel Pump Install 305 merc

Many mechanics do not understand that electric fuel pumps push fuel, they do not suck fuel efficiently. To be properly installed it should be lower than the tank or at least not higher, and should be close to the tank, and not near the end or by the engine.

The mechanical pump mounts to the front of the engine on the left hand side if you are standing if front of the engine looking toward the stern. It sits behind the front motor mount and if it has been removed there most likely will be a flat plate with 5 holes mounted to the block where the pump goes, it is possible that there is a plate with a second plate attached that would only have 2 mount holes. There is also a push rod that goes up a bore from the pump to the cam shaft that runs the pump, it most likely will be gone as well.

easy fix.

That is not the way that I would install the electric fuel pump.

 

[Bondo]

Re: Fuel Pump Install 305 merc

Many mechanics do not understand that electric fuel pumps push fuel, they do not suck fuel efficiently. To be properly installed it should be lower than the tank or at least not higher, and should be close to the tank, and not near the end or by the engine.

Ayuh,....I Disagree higgy,...
In Boats,....
The fuel tank is pretty much Always higher than the motor,+ the fuelpump if mounted there....
It's a Boat,... They All sit at a somewhat Nose Up attitude...
And,....
Boat Gasoline tanks draw from the top, thru an Anti-siphon Valve....
It takes Vacuum from the pump to Suck the fuel thru it...
Line lost is minimal, so it's not important, if the pump Sucks at the motor, or at mid-ship at the tank really Don't Matter,...
And it's Safer to keep everything in the Motor Bay....

For the system pictured above,...
I'd verify the fuel Hose is marine rated, or use hose that Is, to get Rid of the little clear filter,+ mount a Cannister type that should be there,...
And to move the fuel pump down out of the way, more under the manifold...
Then of course making sure it's wired thru an oil pressure switch for runnin',+ from the starter solenoid for startin'....

 

[soaringhiggy]

Re: Fuel Pump Install 305 merc

fair enough, my tank most certainly is lower than the engine, but that is exactly one boat type.

Even if the tank is drained from the top, as most tanks are BTW, having the pump lower still helps as the system siphons from the tank as well, one of the functions of the anti siphon valve is to minimize the amount of vac needed to start the fuel flowing again. Still, these pumps are not good at and were not designed to pull a vac, they are designed to push fuel.

I will absolutely agree that it should remain in the engine compartment.

depending on where the tank is mounted would affect the amount of pull a pump like that would have to overcome, if it is in the bow or under the front seats it could be a 10 or more feet, farther than an automotive application.

Just something to thing about.

 

[Rat Capri]

Re: Fuel Pump Install 305 merc

that pump your "mechanic" used is absolute crap...i recommend one of these

http://www.jegs.com/p/Carter/Carter-Universal-Marine-Electric-Fuel-Pump/1145238/10002/-1

and install a proper water separater/filter unit

 

[soaringhiggy]

Re: Fuel Pump Install 305 merc

that pump your "mechanic" used is absolute crap...i recommend one of these

http://www.jegs.com/p/Carter/Carter-Universal-Marine-Electric-Fuel-Pump/1145238/10002/-1

and install a proper water separater/filter unit

Well that is a bit harsh, they are not bad pumps, it just is not the best pump for this application.

They are very good as booster pumps on RV's as that is what they were designed for.

 

[Rat Capri]

Re: Fuel Pump Install 305 merc

Well that is a bit harsh, they are not bad pumps, it just is not the best pump for this application.

They are very good as booster pumps on RV's as that is what they were designed for.

maybe, but I havent had any luck with those inline type pumps in any application and that looks to be a cheap "off shore " model

 

[flatiron14]

Re: Fuel Pump Install 305 merc

Thanks guys for all the great advice. Yes, a certified Mercruiser mechanic put that setup on. Kinda baffles me because he's been in business a long time and several friends of mine have been using him for years and swear by him... I guess everybody messes up every now and then. So what kind of filter do I need to go with, here? Should the filter come before or after the pump?
-James