Fuel issue GEN III cool fuel


C

castines

Administrator
Hi all,

2 weeks ago went on a 16 mile run headed up river. Start em up, head out. on off plane 4 times with at least a mile in-between then the last part of the trip is no wake zone for about 20 to 35 min. Port engine stumbles while running between 700 to 800 rpm and stalls.

Checked fuel filter, fuel hose to pump, antisiphon valve and fuel level in the tank. Spent about 2 hours troubleshooting and still would not start, fired a few cylinders but not enough to stay running.

Spent the night, woke up in the morning had some coffee while I made a list of tools I would need. Figured I would give it a try. 3rd time cranking she fired right up. No issues the whole way home, reverse no wake at front and hardly any at the end.

The next week make the same exact run and it does it again, only this time about 1/4 mile earlier than before, boat was loaded with people this time for a day trip.

I thought this might be a heat problem with the cool fuel, not sure if it has sensors or not. Took a big bag of ice and put it on the cool fuel unit. 40 minutes later she fired right up. We left about an hour after that. Fired right up, ran for about 10 min in no wake and she stalled again. Put more ice on her and waited til I was passed the long no wake zones. She fired up and ran good all the way back to the slip. Again just 2 small no wake areas.

I grabbed the laser temp gun and shot both fuel cans, the port cainister is running 25 to 30 degrees hotter than the STBD. STBD is like 80-85 PORT is over 100 at times. Even feels different to touch.

Port water pressure reads higher that the STBD on the smart craft.

So is it possible that there is some sand or a clog in the cooling tubes that are in the can or in the hoses that run water thru it to cool it?

$900 fuel pump buys a lot of bags of ICE and keeps the drings cold too :eek:

2007 8.1 375HP Bravo III GENIII Cool Fuel Pump Assemly

Any help appreciated.
 
Check with your Merc Mechanic. If I'm not mistaken there was a Service Bulletin re: Cool Fuel Module whereby the inside of it is painted and unfortunately the E-10 Gasoline causes the paint to come off which clogs the Cool Fuel Module.....
 
Correct me if I am wrong but I am over 5 years so wouldn't the warranty be expired? Or is this bulletin good for out of warranty? Will check engine serials tomorrow
 
Hello
I have a 31 PC 496 mags , current hours 229
was having same problem last season ( have 2 post on forum )
Then the star board engine died on me , and it wouldnt restart , fuel pump went out , found out issue with them , changed out pumps and regulators in both engines .
Engines ran , but just didnt seem the same , and would die at idle speeds , so over the winter , changed both pick up tubes , anti siphon valves ( purchased from fuel tank manufacture ) and ran new fuel lines from anti siphon valves to fuel pump modules .
Formula did have an issue with the pick up tubes , as I found with the old ones ( now Florida Fuel Tanks ships the tanks to Formula with the pick up tubes and check valves installed ) , but unfortunately after doing all that over the winter , when I ran my engines for the first time , the port engine died out , to find that the fuel pump went out , so ended up changing the complete module assy.
Engine started , ran good , but when idling ( which we all have to do going thru no wake zones and pulling in and out of harbors ) the fuel pressure starts dropping , and it dies out .
So after doing more testing , found out the low pressure pumps dont seem to have the capacity to draw fuel from the tank thru the anti siphon check valves to keep the fuel rail pressure at 38 psi , so I bypassed the check valves , and now the engines run FANTASTIC . So now I am seaching for brass anti siphon check valves or possable fuel tank shut off valves .
Note the service bullentin will show you the changed the fuel pump module design , because of the water line fittings , but know where does it say when you pull the cover off to access the fuel pumps , you may find the paint that was used , ( yes the inside of the housing is painted ) doesnt go good with gas , and the paint comes off and plugs up the pumps and regualtors .
 
Re: Fixed Fuel issue GEN III cool fuel

Thanks all.

I removed the water lines to the cool can. They were pluggd up pretty good with corrosion from the aluminum cool module. Ran water from garden hose thru the can to clear it out. reconnected the hoses, be careful, you will need new orings when you do this. Can use the old ones.

Went for a ride and now both cool cans are at same tempeture, nice cool 72 degrees.

So must have not been the paint, just getting hot and shutting down.
 
I have a 2006 34 PC and had the same problem. After some research on the internet and discussions with a mercury mechanic this due laminating of the paint on the fuel pump housing is not uncommon nor inexpensive to repair. One fuel pump housing later, the boat runs fine. I have been advised that I should also replace the port side before I break down again
 
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