Mercruiser 5.7 efi fuel pressure tester kit from Autozone

fotonews

Seaman
Joined
Jun 8, 2013
Messages
58
Hello, will someone be kind enough to tell me if the [h=3]Actron/GM TBI fuel pressure tester part # CP7817[/h] will work to test fuel pressure in my Mercruiser 1998 5.7 efi??

Thanks!!
 

96lt4c4

Petty Officer 2nd Class
Joined
Jan 8, 2008
Messages
110
Wont work, you will have to make one up, or at least I had to. The fuel fittings that Merc used on the TBI are inverted flare like a brake line. Luckily I had some fittings that just happened to fit that came from a transmission cooler that I had bought. I can take a picture of mine if you like.
 

Moonstruck

Cadet
Joined
Jun 16, 2014
Messages
24
You need Mercruiser part (tool) # 91-806901. This will provide you with a standard schrader valve where you can attach your fuel pressure gauge. Is your engine a MCM 5.7L EFI with TBI fuel injection with a MEFI-1 ECM? If so, I have one of these and have dug deep into it. Is it running well? If not, what is the problem, I may be able to help.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
What kind of issue are you trying to solve? Does it have the VST fuel pump? I just rebuilt mine.
 

fotonews

Seaman
Joined
Jun 8, 2013
Messages
58
its a mercruiser 1998 5.7 efi serial #0L012408, the issue is engine starts fine from cold and can run for a while with no issues but at some point after 20 min-45 min or more its starts hesitating and dies completely. If engine is warm it will not start unless i wait for engine to cool off. I installed to new engine compartment blowers and run constantly, i doubt temp in bilge too high, Its a fuel cooler no VST. But again, my question is: is there suppose to be a pocket of air in the line between tank and filter??
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,189
My question is: is there suppose to be a pocket of air in the line between tank and filter??
No you don't want to see a lot of bubbles in the fuel flow between the tank and filter. A small bubble here a small bubble there shouldn't be a great concern but a lot or one big bubble is. Inspect the fuel tank and fittings.


Installing a inline low pressure booster fuel pump may help with any vapor lock but you'll need to find and repair the bubbles first.

http://www.crowleymarine.com/search_results.html?string=0l012408

Good luck.:)
 

alldodge

Moderator
Staff member
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Mar 8, 2009
Messages
42,951
its a mercruiser 1998 5.7 efi serial #0L012408, the issue is engine starts fine from cold and can run for a while with no issues but at some point after 20 min-45 min or more its starts hesitating and dies completely. If engine is warm it will not start unless i wait for engine to cool off. I installed to new engine compartment blowers and run constantly, i doubt temp in bilge too high, Its a fuel cooler no VST. But again, my question is: is there suppose to be a pocket of air in the line between tank and filter??

You didn't mention that it starts doing this after sitting for 20-45 minutes as I read your post. My impression is this is happening just by running around and not stopping for very long. If this is correct, have you checked to see if your anti-siphon valve is sticking, your gas tank vent is open and your not drawing a vacuum? Does the length of time between when it starts to hesitate have anything to do with how much fuel you have in the tank?
 
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