haulinit

Today took the boat out unloaded it went for a short spin out onto the lakes main body it was really rough so I turned around when I started to turn, the boat started to drop RPM . It feels like a rev limiter, motor pulls up to 2300 then thats it. Starts fine idles fine, it free revs fine. The motor is a procharged 502 mag EFI, the fuel pressure was running normal. It has a MSD soft touch rev box, dont know when the cap and rotor was changed pulled the plugs when I put new exhaust manifold gaskets on it and they looked new. I dont really know the maintenance records on the motor. Where should I start? Does the MEFI system have a limp mode in the computer?

GTOFFSHORE

Check fuel water sep. That will keep rpms down.

haulinit

Thanks that was on my list of things to check.

haulinit

Does the ECU know when the boat is in gear?

haulinit

I think the motor is making oil now. Right before it started acting up I changed the oil it looked fine, I put fresh oil in it then it started acting up and now the oil is milky! Are 502's mags know for blowing head gaskets or cracking heads? The motor ran great then all of a sudden all of this! How much oil should a EFI 502 mag hold total? The short time the motor ran the oil or water temp never got to temp.

firehawkcat

Hopefully it is just the gasket not the head

haulinit

I cant verify that the motor is making oil but we keep pulling it out through the dipstick tube and it keeps showing high levels. We are going to try and get the drain plug out, to get whats in there out, but its a major pain in the arse to get to. The oil is a caramel color and if it is water it is not separating from the oil. The motor only has a few minutes of run time since the problem reared its head.

cabin fever

I would think if you cracked a head, you would know for sure, by the oil. When I had a intake gasket go, it leaked enough that the oil was WHITE, and there was absolutley no doubt.

Have you down a compression, or leak down test?

Keep in mind the water temp is cold right now, and if you are not getting oil temps out, its gonna condensate. This chit drives me crazy. I'm about ready to buy a canoe!

haulinit

Compression test is next on my list. Havent had much urge to crawl in the engine hatch with the 100 degree heat index lately . Going to try and get the oil pan drain plug out, not having much luck getting all the oil out through the dipstick. Changed the fuel/water filter and it had a bunch of crap in it hoping that was the revving problem but dont know yet.

PatriYacht

If it's making oil, stop running it! There is a major water leak somewhere and it's going to ruin the engine. Procharger leads me to believe it's a head gasket. Do a leak down test. Fix it before running it again and it will probably be ok.