wwolfe

Here is my story....bare with me its long winded but starting to run out of patience. My boat is a 2001 Baja 272 with a 496/425HO with 100 hours

2 weeks ago - Went to poke run and put boat in water and fired and stalled. Tried to re-fire and only turned over and didnt start. Come to find out electric fuel pump not kicking on and priming. Took boat out of water and brought to a mehanic at poker run. Disconnected the relays on top of the motor and blew on them and reconnected. Fuel pump went on and boat fired. Put boat back in water and fired up at dock. Went to join run and got and plane then started pulling throttle back around 3000 rpm when motor started to detonate and pop/bang. Boat went off plane to idle. Tried few more times and same result. Went back to dock and changed fuel/water separator. Took boat back out and everything worked great rest of the day on a 70+ mile poker run. Ran boat next day burned through all fuel and ran great.

1 weeks ago - filled boat with 70 gallons mobil 89 octane and used stabil marine stabilizer in fuel. Pulled boat 200 miles to Alex Bay and fuel pump did not kick on when we got to launch. Took apart relays again and this time filed them with nail file and used compressed air to blow out debris. Fuel pump came on and boat fired. Used boat all weekend and went to Canada with no issues.

Last Night - Installed 3 new relays and used di-electric grease on all relays along with all other harness connectors on top end of motor. Ran boat with muffs and fuel pump came on and no issues.

Tonight - Put boat in water and fired up and idled out. Went to get on plane and motor started to spit/sputter and detonate and went to idle. Did same thing 3 more times when trying to plane but would idle OK. Changed fuel water separator again and primed motor few times. Motor started but would not run higher than idle and motor sounded like it was running on 6 cylinders and would diesel at idle and die. Got towed back to dock and back on trailer

Did my guardian mode kick in?

Assume one of these 3 issues are possible?
- Low pressure or high pressure fuel pump has now gone bad?
- IAC Valve bad
- Crank trigger bad

I assume my best bet is to bring to someone with a scanner and hopefully now will get a code to figure out what is wrong?

Any and all advice is appreciated!! Trying to get fixed for next weekend to go back up to Alex Bay.

getting frustrated here and need some advice!

Wes

Bajapred

iTrader: (1)

Yep... Definitely sounds like a fuel issue. Sounds like you could be getting some vapor lock too if one of your pumps is weak. Need the scanner to check for fault codes. Doesn't really sound like IAC... Crank sensor maybe, my bet is fuel though.

Ebay Ed

check your fuel pressure

wwolfe

that is hooking up a fuel gauge to the schroeder valve on front of engine near alternator? it should be around 40-45 psi at idle correct? Do you check with key in run position too and motor off?

Ebay Ed

i would check it running going down the water i think it should be closer to 55 but not sure but i dont know where the valve is on a 496

wwolfe

Heres an update on todays findings and answers to some of your questions. Thanks to everyone for your input and Ray especially...i understand you are the 496 guru.

-I changed the fuel water separator out on the water when the boat died (had a spare on board) but didnt have any fuel to put in it and was afraid to put in the fuel from the old one i took off. I primed it with the ignition 5 times prior to starting in the water yesterday. When unscrewed it today and it did not have hardly any fuel in it. I filled it with fuel and reinstalled

- Pulled the plugs and 3-4 of them did not look good. Very black, even the electrode and internal porcelin and smelled like gas and wet. These plugs were installed about 20 hours ago. I reinstalled a new set of plugs today

- Cleaned the main terminal with wire brush and all connectors. Reassembled and tightened appropriately

Put muffs on and boat fired right and sounded great and healthy. Water coming out of the pipes good and responsive.

Taking to my friends marina tomorrow who has a scanner to look at fuel pressure, fuel pumps, crank sensor, and check to make sure fuel lines aren't clogged at screens.

Hope this resolves and successful test run later this week on water under load to see if things are resolved.

Wes