4.3 Mercruiser fuel supply issue

[Jeff J]

“If you disconnect the return line coming from the pump back to the fuel filter (arrow pointing in on filter head). Seal off the filter head and seal off the return line. Have gauge on fuel rail and turn key on/off, maybe a couple times to build pressure. It should go above 43 psi but try not to let it get much higher by using the pressure relief on the gauge.”

I think I inadvertently did this check by installing the primer bulb. It is basically a check valve and forces the excess pressure back the pump. Not sure an anti-siphon valve wouldn’t do it too.

Max pressure I see pumping the bulb while the pump is running is 35. I pulled the 2 nuts holding the bracket but still couldn’t get it to drop down. It’s loose on the studs so probably the cooling hoses holding it. Can’t see anything else. Probably be a couple of days before I get a chance to try again.

If I ever have the need to do this job again, it’s going to a Mercury shop!

 

[alldodge]

If air was bleed out from the rail, then in that case its probably the pump

 

[Jeff J]

Pulled the cooler hoses and got some free movement but now it is hung up on the oil dipstick tube in a tighter spot than it started so I still can’t get the cover off the pump. I hate to give up the income but this thing is getting really close to finding its way to a mercury shop.

 

[alldodge]

Pulled the cooler hoses and got some free movement but now it is hung up on the oil dipstick tube in a tighter spot than it started so I still can’t get the cover off the pump. I hate to give up the income but this thing is getting really close to finding its way to a mercury shop.

Understand, sometimes it's just to much for me also.

If there is room, small bottle jack to lift that side of the motor just enough to remove the the motor mount. Or if you have a hoist

 

[Jeff J]

I did get the cover off. Accidentally knocked the bottom loose then used brute force to twist it out. Didn’t help much. One fuel line I can see needs a key(?) to remove so a trip to NAPA tomorrow for that. The line on the regulator is a flare nut. I have SAE flare nut wrenches but none in metric. I doubt there is room to work it where it is anyway. I didn’t get a look at the line coming from the filter to see what it takes to undo.

Thanks for the tips. I have several ways to possibly lift the motor so I may try removing the motor mount tomorrow. I have done a few motor mounts but not on a boat. For that matter, I have never looked at how an inboard is mounted. Is there anything I should disconnect, take loose or keep an eye on if I go that route?

 

[alldodge]

Your say "inboard" but thought you had a I/O
If it's a I/O then remove the drive before jacking up motor
If inboard, remove prop shaft coupling before jacking motor

 

[Jeff J]

I am bad about using proper terminology. Did not know better most of my life and bad habits die hard. It is an I/O.

I have no idea what disconnecting the drive entails so I guess I will be searching the manual and youtube for that too. I let the local service center do engine removals, gimbles, bellows and driveshafts.

Thanks for the heads up.

 

[alldodge]

Removing the drive is easy for the most part

With a Alpha drive move throttle full forward (don't use throttle only it needs to be in forward)
Trim drive so it's straight up and down
Remove pin from rear trim cylinders
Remove six bolts holding drive and then slide drive out

Might need a block of wood under drive to sit it on once out

 

[Lou C]

Pulling the drive is easy compared to what you're doing now!
How about laying a strong wooden beam across the gunnels, padded where it lays on the fiberglass and use a strong enough ratchet strap to just lift the engine high enough to get access?
You guys with the newer engines have my sympathies.
I'll take a pre-vortec engine with a mechanical pump and 4 bbl carb anyday!

 

[Jeff J]

Yeah, I won’t own a newer I/O for myself. It’s bad enough dealing with it for pay. The next one in line has a Volvo Penta needing a trim pump. Not a terrible job but a lot of blind groping around while laying on top of the motor trying to get it installed and hooked up. Rumor has it this outfit going to start swapping out boats to standardize the fleet. Fleet currently has 5 different makes of motors with 8 different sizes. 6 makes if you count the Honda that hasn’t run in 5 or so years. 7 different makes of boats of varying models and sizes. I am hoping for all outboards in the new fleet. I made the pitch to the powers that be to save money, time and hassle. It’s hard to winterize a boat that needs work. Might need to be winterized more than once if it has to be trailered or when more than one needs trailered because we don’t have trailers for everything.

Enough stalling. Time to go see what else has to be done to finish this one.

 

[Jeff J]

I ended up turning this one over to the local Mercruiser service center for lack of tools/equipment to remove the outdrive and raise the motor shortly after my last post. I don’t have what I need to do it “right”. Apparently there were some missing parts because they called me asking about a bolt missing from the pump and a washer. I didn’t remove anything from the pump. They still have the boat. I don’t know what is special about the “washer” but it is backordered and holding up the show. Good thing the season is over and that’s the least popular boat in the fleet.

 

[Fun Times]

local Mercruiser service center asked about a missing bolt and washer. I don’t know what is special about the “washer” but it is backordered and holding up the show

Maybe they are missing the copper washer that goes into the fuel regulator fitting item number 18?, https://www.mercruiserparts.com/bam/subassembly/31507/13808/60

If yes or even no, try to get the merc part number and run it through ebay and see if you get a hit...You'll probably get it a lot quicker than they will by ordering it for them.

12-36533 Washer in eBay Motors for sale | eBay

www.ebay.com

Here's your parts catalog for your engine model,

4.3L MPI ALPHA/BRAVO - 1A063240 & Up

4.3L MPI ALPHA/BRAVO - 1A063240 & Up

www.mercruiserparts.com

 

[Scott Danforth]

or go to napa for the copper crush washers in the cabinet near the front door and you can get it today.

 

[Jeff J]

Is it supposed to a plain copper washer or a true crush gasket. If the latter, I may have one out in the hangar.

 

[Jeff J]

We got the boat back from the shop. The bill was about $3700 for a fuel pump change. The engine work is done and lake tested but I still have to crawl in there to put the hull back together. Season is over so no rush.

 

[Lou C]

That's completely insane.
People make fun, but that's why I kept the old boat.
Mechancial fuel pump from Carter, marine version, don't have to buy from the robber barons at Mercruiser or VP, $50, they last a LONG TIME. Can be bought at Jeg's or Summit Racing.
Carb rebuild kit, the best Quadrajet kit from Cliff's High Performance Quadrajets, about $60. A well tuned Quadrajet, runs as well as throttle body injection, except for cold starts. So much for progress.....

 

[nola mike]

That's completely insane.
People make fun, but that's why I kept the old boat.
Mechancial fuel pump from Carter, marine version, don't have to buy from the robber barons at Mercruiser or VP, $50, they last a LONG TIME. Can be bought at Jeg's or Summit Racing.
Carb rebuild kit, the best Quadrajet kit from Cliff's High Performance Quadrajets, about $60. A well tuned Quadrajet, runs as well as throttle body injection, except for cold starts. So much for progress.....

Yeah, as much as I'm tempted by a newer boat with an ob, a 21' with a 350 carb (or 383, why not) I/o would be tough to pass up from an ease of repair pov

 

[Scott06]

Yeah, as much as I'm tempted by a newer boat with an ob, a 21' with a 350 carb (or 383, why not) I/o would be tough to pass up from an ease of repair pov

Look under the cowl of a modern 4 stroke, thee are some chit burgers waiting under there as well. My brother has a Yamaha 50 hp 4 stroke fantastic machine but its tight under there too. Also has a timing belt that need changing

while a lot of IOs have too much boat around them strikes me as 6 of one half dozen of the other. Sure some winterization advantages but I wouldn’t give up my swim platform for an afternoon of work one day a year

 

[alldodge]

If they made I/O's without CATs I probably would have in instead of OB, but no go since 2012

 

[nola mike]

Look under the cowl of a modern 4 stroke, thee are some chit burgers waiting under there as well. My brother has a Yamaha 50 hp 4 stroke fantastic machine but its tight under there too. Also has a timing belt that need changing

while a lot of IOs have too much boat around them strikes me as 6 of one half dozen of the other. Sure some winterization advantages but I wouldn’t give up my swim platform for an afternoon of work one day a year

It would be nice to just throw it in for our random nice winter days. I took the skiff out on friday--nice 17 mile cruise, but the water really needs to be flat this time of year. A little spray is all fun and games when the water temp is 80', but this time of year, not so much.