Lost power

krudville

Cadet
Joined
Aug 26, 2009
Messages
29
1994 4winns 5.0 omc efi. Cruising along and lost power. surged a couple times , coughed and died. Won’t start. Replaced fuel filter. No evidence of water. Fuel pump?
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,815
Could be that, could also be the anti siphon valve on the gas tank, pick up tube or tank vent. You could try to run it (careful with hooking it up) on a portable tank to rule that out.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,548
1994 4winns 5.0 omc efi. Cruising along and lost power. surged a couple times , coughed and died. Won’t start. Replaced fuel filter. No evidence of water. Fuel pump?
Turn on the fuel pumps manually using jumpers(pin 87 to 30) and measure your fuel pressure.

You may only have one fuel pump on yours.

Can you post your model number?
 
Last edited:

krudville

Cadet
Joined
Aug 26, 2009
Messages
29
Too late to test pressure in the boat. My mechanic, my volunteer son, pulled It. Any way to bench test?
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,548
This is the page that shows the parts of your fuel system. There is another pump besides the one above the filter.


Just so you know, you have a Ford engine, the fuel pumps are available but other parts are hard to come by. Hopefully, its just a fuel pump. If its the ECU, you have a huge problem.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,548
Too late to test pressure in the boat. My mechanic, my volunteer son, pulled It. Any way to bench test?
It needs to be pumping fuel to test. The bigger problem is testing the high pressure pump. I have zero idea how to test this Ford high pressure pump.

I do not have a manual for this engine. That's the first thing you need to get before you proceed any further
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,548
Thanks. We‘ll take a look. I’ve been looking like crazy for a service manual.
Buy it right now.

For future reference you have an MD model. The Volvo MD and the OMC MD are identical since this is one of the joint venture years.

Another BTW...a lot of people that have these EFI Fords pull the EFI and put carbs on them when they can't fix the EFI....just a warning for you. Same applies for the distributor since I believe they use the same ECU
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,815
Syn oil is not really needed, I use the standard Merc 25/40 marine oil. Many use the 15w/40 certified for diesel and gas engines.
If you wind up having to change to a carb, you will have to source (used) a cast iron intake for a Ford 302 (5 liter), and Holley does still sell brand new carbs that are calibrated for that size engine. It will run into some money but you will be free of the NLA syndrome of old marine EFI systems, because Holley parts are everywhere in the aftermarket.

This is calibrated for the Ford 5.0

the distributor is more challenging, here is what shows up in the OMC catalog for your engine/year, it does not look like the Prestolite BID system used on the GM V6s and V8s.

there is this, I have no idea on how good they are....
 

krudville

Cadet
Joined
Aug 26, 2009
Messages
29
Where is the anti siphon valve located? I was told this is a common problem with my boat. By the gas tank?
thanks
 

PITBoat

Petty Officer 1st Class
Joined
Jul 26, 2018
Messages
286
It's the thing the fuel line attaches to that's coming 90deg off of the pickup tube, right outta the tank.
 
Top