Mercruiser 3.0 fuel pump questions (unknown year) no SN

[wahooper1]

I have a mercruiser 3.0 and there is no SN plate on the block by the starter. There is the sticker for the transom assembly on the valve cover which is 0B812797.
It seems that the previous owner threw parts at it to make it complete and run. The fuel pump has now went out and am looking to figure out which pump is the right one. The current pump is a Carter 0-3035 which has no filter attached, I have no clue what that is supposed to go on. From what i understand is there are only two pumps for the 3.0 --- a bowl down and a bowl up. I have already tried the bowl down pump and it doesn't seem like the right pump because the finger on my current pump points up. Can someone help me with this MESS??

 

[achris]

Hello wahooper1 and :welcome:

First off. Any fuel, electrical or ignition system parts you put in MUST be 'marine' rated, SAE-J1171...

That serial number is for a TR/TRS drive, and the 3 litres were never fitted with a TR or TRS drive. So, let's have a guess at the age. 1986 (if the 0B.... serial number is remotely accurate)....

All the 3 litre blocks are pretty much the same as far as Fuel pump mounting goes, so all good there. The 'bowl down' pump and the 'bowl up' pump mount to the same face, and the arm on the pump works the same whether it runs on the top of the cam lobe or the bottom... They will be designed only to be mounted one way, you can't choose that.

The 'bowl down' pump is the later one and it's part number -42725A3. The 'bowl up' pump is -86234A4. Each runs a different hard line to the carburettor, so whichever you have now, go to that one or be replacing the fuel line too.

Chris........

 

[wahooper1]

Alright so I got a "bowl up" pump and it interferes with the distributor that is on the motor. So i put on the "bowl down" pump and got some new hardline and am bending it right now (I'm on a break... Its hot down here in Tampa!) I did some research last night and it appears that the pump i took off as well as the carb. came off a 92 OMC. The distributor is the EST version off of a 92 Mercruiser. The boat is a '93 with a alpha one Gen. 2 that originally had a 3.0 mercruiser. The old block had a crack and the previous owner found a 3.0 block and put parts on it until it ran...

 

[wahooper1]

Update!

The new fuel pump is dong its job great! The boat now will idle all the way out of my canal now but when i get to open it up as soon as i give it some throttle it will shut off. I'm going to check for water in the gas and check timing tomorrow!

 

[savetexomabeaches]

when you give it throttle, it shuts off? do you mean it bogs down, or instantly dies?