Install mechanical fuel pump- mercruiser 357

[Ramanonos]

I thought this would be an easy job, but I'm tearing my hair out. I have new mechanical fuel pump going on a Mercruiser 357 carb 5.7L. The old one came off very easily. I cant seem to line up the bolt holes in getting the new one on. I feel like I'm missing something obvious. I noticed the pushrod is fully extended inside the cam. I tried "wiggling" it around. No luck. The pump itself has a massive compression. I thought about muscling it in, but Im afraid to pull dumb-*** tactics where I brake something. Is there a wonderful trick/tip someone can enlighten me on? Thanks!

 

[Eric 3.7LX Alpha 1]

Re: Install mechanical fuel pump- mercruiser 357

A little trick you can do, using a socket and ratchet on the engine balancer. SLOWLY rotate the engine by hand and feel the fuel pump push rod with one finger of the left hand. Be careful where you put your finger!!! on the very bottom of the push rod not the sides of it!!!

The camshaft lobe will push it down and then it will go back up. (you may have to help push it up there, that's what the fuel pump does, the cam pushes it down and fuel pump pushes it back.

It's probably at the bottom of it's travel. While it is "up" install the fuel pump, so you are not fighting the fuel pump push rod, should be much easier

 

[Bondo]

Re: Install mechanical fuel pump- mercruiser 357

A little trick you can do, using a socket and ratchet on the engine balancer. SLOWLY rotate the engine by hand and feel the fuel pump push rod with one finger of the left hand. Be careful where you put your finger!!! on the very bottom of the push rod not the sides of it!!!

The camshaft lobe will push it down and then it will go back up. (you may have to help push it up there, that's what the fuel pump does, the cam pushes it down and fuel pump pushes it back.

It's probably at the bottom of it's travel. While it is "up" install the fuel pump, so you are not fighting the fuel pump push rod, should be much easier

Ayuh,.... 'n after ya do what Eric says,...

On many blocks there's a bolt on the front, goin' back, that aligns Perfectly, with the fuel pump push rod...
Ya remove that bolt, 'n screw in a slightly longer 1,...
Gently finger tighten it against the push rod, 'n lock the rod, Up, 'n outa the way...

Just make sure ya remove it before firin' it up...

 

[Don S]

Re: Install mechanical fuel pump- mercruiser 357

Gently finger tighten it against the push rod,

That means more than you think. If you damage that rod, or leave a mark on it, you will have problems.

 

[onsiteservice]

Re: Install mechanical fuel pump- mercruiser 357

Even at the top of the lobe you will still have to put pressure on the pump pulling it upwards toward the cylinder head in order to line up the bolt holes. Your not going to damge the pump, if you do you're the man LOL....Another thing that has worked very well for me in the past if you do not have an alignment hole in the front of the engine block, is to remove the two bolts under where the fuel pump sits and remove the plate. Remove the rod and on the engine/cam lobe side put a dab of grease on it. The grease will help hold it in place and will not damage the engine upon fire up. Thery're not much fun to do on an engine stand some days let alone while standing on your head! Goodluck!

 

[Ramanonos]

Re: Install mechanical fuel pump- mercruiser 357

Got it in, but that was awful. The rod wasnt stuck. Its just very lubed and impossible to move up with the backing plate in place. But i did need to get the pump lever under that wretched slippy rod-- and keep the pump in place while blindly screwing in the bolts (bayliner cierra with a 357 gives you a few inches of clearence to do work down there...). Anyways, not complaining, i thought id share a neat trick to make it less awful for the next guy. Get an old hack saw blade and bend the end to form an L. Slide the lip of the L down the lip of the plate to push the rod up. While leaving the blade in, put the pump in with the lever under the blade (and rod). Loosly tighten both bolts so the pump is on the block, and the lever is under the rod. And then slide the hack saw blade out. Done. After about 2 hours of swearing, I figured out this trick and had the whole thing on in 15mins. Good luck to the next guy. And thanks for all the input. She runs!

 

[onsiteservice]

Re: Install mechanical fuel pump- mercruiser 357

Never heard of that one....LOL....a little creative problem solving! Good Job!

 

[ktbarrentine]

Re: Install mechanical fuel pump- mercruiser 357

Got it in, but that was awful. The rod wasnt stuck. Its just very lubed and impossible to move up with the backing plate in place. But i did need to get the pump lever under that wretched slippy rod-- and keep the pump in place while blindly screwing in the bolts (bayliner cierra with a 357 gives you a few inches of clearence to do work down there...). Anyways, not complaining, i thought id share a neat trick to make it less awful for the next guy. Get an old hack saw blade and bend the end to form an L. Slide the lip of the L down the lip of the plate to push the rod up. While leaving the blade in, put the pump in with the lever under the blade (and rod). Loosly tighten both bolts so the pump is on the block, and the lever is under the rod. And then slide the hack saw blade out. Done. After about 2 hours of swearing, I figured out this trick and had the whole thing on in 15mins. Good luck to the next guy. And thanks for all the input. She runs!

That hacksaw blade trick was actually written in the instructions for the replacement fuel pump I bought. I ended up using the grease and fishing line trick, instead.

 

[lister]

Actually wait a sec. Take a look at this picture. Is this fuel pump upside/wrong? Or do some go this way round?

http://www.shipwrecksalvage.net/imag...gine-Motor.JPG

(sorry this is an old thread thought it was mine but the question remains. Is this ok or not ever?)

 

[Fun Times]

Actually wait a sec. Take a look at this picture. Is this fuel pump upside/wrong? Or do some go this way round?

http://www.shipwrecksalvage.net/imag...gine-Motor.JPG

(sorry this is an old thread thought it was mine but the question remains. Is this ok or not ever?)

Hi there lister, Please know that the hosts of iboats prefers old topics like these remain down in the archives and normally go unanswered but to help close this one out for you I'll help you real quick and say yes this fuel pump at one time was designed to mount the way you found the photo above.

The old pump linked below is like the one you found while the new design is the other way around.

FUEL PUMP AND CARBURETOR(OLD DESIGN)
FUEL PUMP AND CARBURETOR(NEW DESIGN)

Gotta close this one up now.