6.0 Marine Power issues

[bigtige72]

I have a 2004 24V with the 6.0 375 hp Marine Power in it. I went out Saturday, and had no issues. Sunday I started the boat put it in the water, and as I was idling around filling my ballast bags, the alarm came on constant. The engine would die intermittantly, and would crank and restart but the alarm stayed on. Temps looked fone, voltage was good, and oil psi was good as well. As the engine sat and idled it would ramp up and down, loping or hunting to find idle. It also smelled like it was running rich, but I was thinking it was a fuel filter or a fuel pump issue. I haven't had a chance to take it to a marina yet, but wondered if anyone had an idea. Also, does anyone know the part number for the fuel filter for this engine?
Thanks!

[The Black Widow]

You are in luck because I just did all this research for my fuel filter/pump. You can find the high pressure pump kit here http://marineenginedepot.com/MP/Mari...and-Cannister/ or if you are just looking for the filter it is part number 396007 (http://marineenginedepot.com/MP/Mari...rce-Fuel-Pump/)

Our issue was the engine was running rough at idle and then dying. We replaced the low pressure pump only and its running great again.

[bigtige72]

Thank you so much!!!

[Dave K]

I have a 2004 24V with the 6.0 375 hp Marine Power in it. I went out Saturday, and had no issues. Sunday I started the boat put it in the water, and as I was idling around filling my ballast bags, the alarm came on constant. The engine would die intermittantly, and would crank and restart but the alarm stayed on. Temps looked fone, voltage was good, and oil psi was good as well. As the engine sat and idled it would ramp up and down, loping or hunting to find idle. It also smelled like it was running rich, but I was thinking it was a fuel filter or a fuel pump issue. I haven't had a chance to take it to a marina yet, but wondered if anyone had an idea. Also, does anyone know the part number for the fuel filter for this engine?
Thanks!

Have you had a rough running problem since you have had the boat or did it just start? Does it have when engine is cold or hot or both?(not sure how long you have owned your boat).

If it has been doing that from day one, after it has been running I had a similiar problem. The problem was because of engine heat in compartment, fuel was getting warm/hot in the fuel line close to the engine thus creating some sort of vapour lock. The fix was a update fuel return line that was installed.

Since that was done my 6 litre 380hp has run great !!!!

[bigtige72]

It has ran fine since I bought it a year ago, I have noticed that it gets a vapor lock, or something if I run it, and shut it off and let it sit for a while it will have an extended crank. It does it worse if I fill will ethanol blended fuel, which is pretty often since here in Oregon they passed a stupid ethanol blend law... but it just happened all of a sudden. I had no problems with it, and then the alarm came on, and the engine lopes, or revs up and down.... figured maybe a fuel filter, or a fuel pump issue!!

[boatwakes]

Check your fuel pressure first. There's a schrader valve (think bike tire) on the fuel rail for a gauge. When you hook it up and run it, the fuel pressure should remain steady when the engine is running. If not, your pump is failing, if it runs ridiculously high or low, it's the regulator. If it runs for 3 minutes and then starts doing it, your anti-siphon valve is the problem. If the fuel pressure is fine, look at your throttle position sensor and idle air control valve.

[bigtige72]

I did change the fuel filter yesterday, made no difference. I did not check fuel pressure at the fuel rail, but the problem now seems intermittent, I ended up taking it to the Marina in town, and I'll let them figure it out! I don't have time to deal with it... But kinda figured it's a tps, or something...

[bigtige72]

So, after taking it in to dealer, they found the fresh water impeller bad, it was soft and spongy, and missing a couple teeth. Replaced the impeller tested it again, and had no problems. Really weird that the impeller would cause a rpm hunt....

[boatwakes]

I re-read your original post and have a question: do you start the engine out of the water and then launch it? If so, don't do that, it's why your impeller was bad.

[bigtige72]

No, never do that! I learned that with my first boat... lol!