Pooched fuel pump.... need replacement options

[ScottinAZ]

Ok, engine is a 1980 120hp 2.5l. Fuel pump appears to be pooched, and is NLA through all sources I have seen. Not totally married to the idea of an engine driven pump, so looking for options. (Mercruiser p/n 86234A4 for the whole pump, or 49089A1 for the diaphragm kit). Sierra shows a 18-7278 in their catalog, but everyplace I have looked is out of stock, or unobtanium.

First, is the mount and lever by chance the same as a small block V-8 or inline 6 Chevy? these are everywhere, but dont have the internal filter (zippidy doo dah.... ill run an external)

Second, is there a popular external electric option that is "marine approved" for those of us that want to continue using obsolete technology (because it still works....) Just need to run a block-off plate on the engine and remove the mechanical pump.

 

[alldodge]

Amazon shows in stock
https://www.amazon.com/MerCruiser-Replaces-86234A4-86234A05-18-7278/dp/B07N31DZQ4

 

[ScottinAZ]

Amazon shows in stock
https://www.amazon.com/MerCruiser-Replaces-86234A4-86234A05-18-7278/dp/B07N31DZQ4

it figures.... I punched in the sierra and mercruiser numbers and got gibberish...... sometimes I really hate their site.... Thanks!!!!

 

[Scott06]

Ok, engine is a 1980 120hp 2.5l. Fuel pump appears to be pooched, and is NLA through all sources I have seen. Not totally married to the idea of an engine driven pump, so looking for options. (Mercruiser p/n 86234A4 for the whole pump, or 49089A1 for the diaphragm kit). Sierra shows a 18-7278 in their catalog, but everyplace I have looked is out of stock, or unobtanium.

First, is the mount and lever by chance the same as a small block V-8 or inline 6 Chevy? these are everywhere, but dont have the internal filter (zippidy doo dah.... ill run an external)

Second, is there a popular external electric option that is "marine approved" for those of us that want to continue using obsolete technology (because it still works....) Just need to run a block-off plate on the engine and remove the mechanical pump.

if you google the part number you find a number of replacements for the
OEM part, which has been superceeded by 8623A5..

mercruiser 86234A4 - Google Search

nothing wrong with a mechanical pump but you can do electric carter makes marine universal fit electric pumps, just need to wire it through an oil pressure switch so it shuts off off engine is not running but igniton is on...

 

[ScottinAZ]

if you google the part number you find a number of replacements for the
OEM part, which has been superceeded by 8623A5..

mercruiser 86234A4 - Google Search

nothing wrong with a mechanical pump but you can do electric carter makes marine universal fit electric pumps, just need to wire it through an oil pressure switch so it shuts off off engine is not running but igniton is on...

looking at the electric as the preferred option. The fuel tank mounts on the port side of the engine bay, same side as the carburetor. Of course the mechanical pump is on the Stbd side, so you have the line crossing over behind the exhaust riser and then from the pump back over the top of the engine to the carb (I dont like this idea). If I go with electric, I can keep all the fuel on one side of the boat shortening the lines and limiting the amount of exposure for leaks. Wiring isnt an issue, I was an aircraft electrician in the Navy, so that is second nature to me. I can easily tee into the oil pressure port for the kill switch.

 

[itsathepete]

Amazon.com

This should work nicely for your application. I would install an oil pressure switch that closes when oil pressure comes up.

Edit: I see you are already on board with the oil pressure switch

 

[Scott06]

looking at the electric as the preferred option. The fuel tank mounts on the port side of the engine bay, same side as the carburetor. Of course the mechanical pump is on the Stbd side, so you have the line crossing over behind the exhaust riser and then from the pump back over the top of the engine to the carb (I dont like this idea). If I go with electric, I can keep all the fuel on one side of the boat shortening the lines and limiting the amount of exposure for leaks. Wiring isnt an issue, I was an aircraft electrician in the Navy, so that is second nature to me. I can easily tee into the oil pressure port for the kill switch.

Look up the merc wiring diagram on my boat they run in parallel 12 off the starter when cranking then when in run it comes off the 12v + to coil (purple) through the oil pressure switch to power the fuel pump.

If you search these forums you will see threads showing diagrams and commonly available relays to power it up

 

[ScottinAZ]

Look up the merc wiring diagram on my boat they run in parallel 12 off the starter when cranking then when in run it comes off the 12v + to coil (purple) through the oil pressure switch to power the fuel pump.

If you search these forums you will see threads showing diagrams and commonly available relays to power it up

on mine I have just an oil gauge and no warning light. 12v from starter to coil, and then a resistor wire for the normal run position. Ill come up with something, its not an earth shattering deal to rig in an on/off oil pressure switch into the 12v side of the pump, with an alternate for starting (with no oil pressure) off the side of the solenoid parallel with the 12v start supply to the coil. IIRC a standard Chevy oil pressure light switch will do the deed just fine. ( gotta double check though, it could be reverse wired for what I need..... that would suck)

 

[Scott Danforth]

Carter still makes the mechanical fuel pump

 

[itsathepete]

I just added a fused wire from from the keyed hot side of the alternator to the fuel pump then run the negative to the oil pressure switch and ground the other terminal to the engine block. I didn't run it off the starter because I didn't see the need for a carbureted engine. It will start with the fuel in the bowl and pump as soon as oil pressure picks up. The switch doesn't need much oil pressure to operate so it will kick on during cranking even if the engine isn't running

 

[ScottinAZ]

I just added a fused wire from from the keyed hot side of the alternator to the fuel pump then run the negative to the oil pressure switch and ground the other terminal to the engine block. I didn't run it off the starter because I didn't see the need for a carbureted engine. It will start with the fuel in the bowl and pump as soon as oil pressure picks up. The switch doesn't need much oil pressure to operate so it will kick on during cranking even if the engine isn't running

my thoughts on this were even though its a carbed engine, 99% of the time, it will be sitting idle with the fuel in the float bowl possibly evaporated out. Getting it juice with the start circuit gives it a head start on refilling that float bowl and getting a good fire off without a lot of cranking. We are in AZ, so that fuel WILL evaporate in short order

 

[itsathepete]

my thoughts on this were even though its a carbed engine, 99% of the time, it will be sitting idle with the fuel in the float bowl possibly evaporated out. Getting it juice with the start circuit gives it a head start on refilling that float bowl and getting a good fire off without a lot of cranking. We are in AZ, so that fuel WILL evaporate in short order

Copy. Should work fine either way, I just go for the simplest solution