dkramer

All,
a few years back I bought a 2000 Baja 272 Boss with a Mercruiser 502 Gen VI MAG MPI. I got through the first season as has a few small issues and knew the engine needed a rebuild. Had about 380 hours and needed some TLC. Had some rust issues. I had a local shop pull the engine and rebuilt the top and bottom end. Well for that next season everything ran well and had minimal issues. End of the season before last the engine started having issues. You would be cruising and just lose power, Engine would backfire and sputter and if you backed off the throttle it would act somewhat normalize and periodically would start going again and when it did you felt like you were shot out of a canon. Was very periodic issue The season was over so I had it winterized and waited to beginning of this past season to have it looked at. I took the boat over to a local place near my new house in Wash Twp., NJ and they pulled the engine as I had an oil leak from a remote oil drain on the oil pan. Long story short while the engine was out ended up replacing the oil pan (old one was rusty) a new knock sensor, few odds and ends. I also had the bellows, gimbal, and the shift cable replaced. Engine went back in and everything seemed fine then same issues started up not too shortly thereafter. Took it back to the shop and they determined one of the injectors was messed up. They replaced the injector and for a brief time it ran decent. Same issues started up again a few weeks later. Totally frustrated I started replacing things. New electric fuel pump, regulator, fuel water separator, dist cap, rotor, wires, the sensor on the dist cap. the list goes on. Same issues persisted. It ran ok but if you got on it it would feel like it intermittently missed. Sometimes worse than others. Needless to say I have about had it. I winterized it up and am back to the drawing board. I have contemplated pulling it and having a full rebuild done again, toyed with removing the fuel injection putting on a electric fuel pump, pressure regulator, new intake and a carb. Some people say this will fix my issues as the legacy Merc Cool Fuel and EFI is plagued with issues, some say that I dont want to get rid of the fuel injection. I'd like your opinions. Fuel Injection or No Fuel Injection? If fuel injection any idea where to start to fix this for good? If I take off the Fuel Injection am I sacrificing anything...docking, cold starting, etc?? Any recommendations on a good and reliable mechanic in the area of Little Egg Harbor, NJ. (Jersey Shore, 20 miles north of AC) and any suggestions and info is greatly appreciated. I have toyed with the idea of just buying a new (well used but new to me) 525EFI. Heading to the boat show this weekend in Miami. Maybe I'll come home with something new!!!

Thanks,
Dave

Dave

tunertech

keep the EFI, your problem is likely a fuel starvation issue, typical from the tank to the Fuel/Water separator.

Check anti-siphon/remove replace main fuel line.

dkramer

The main fuel line was replaced from the pickup to the fuel water separator however the mech fuel pump was never replaced. I have to see if i am able to remove the pickup from the tank and see if it has a ball in the end of it. I'm guessing that if I were to check the fuel pressure at idle it would be ok but maybe not when at WOT. The weird thing is when it acts up some times it will start missing, etc and then backfire periodically. Maybe I should hook it to a portable tank to rule out the pickup / anti syphon?

Thanks
Dave

badmonkey

Same issues...ending up implementing an adjustable fuel pressure regulator to make certain we maintained the appropriate fuel pressure which should be no less than 40 lbs...we have been running well ever since. Speak to Art Lilly at Lilly Sport Boats in Arnold, MD. They were the ones that figured this out.

Good luck..hope this helps you.

FIXX

iTrader: (2)

all good correct above...when you have the fuel pick up out and if its alunimum replace the pick up with the nylon one,,the aluniumum tube will brake where the threads are at the top and suck air...also your boat is a older boat,,it would be a good idea to pull all the injectors and have them cleaned and flow checked,a bad injector will make the boat stumble and miss..

Trash

Not only will it cause a stumble and miss it can also lean out the cylinder(s) and cause much more damage.

TahoeRick

Tell me about it...! I'be got 2 900 HP motors being rebuilt...

ezstriper

not to piss anybody off...but the merc EFI is not a very good setup, switching to a good intake and carb is not a bad and cheap deal....or better yet aftermarket EFI system that is tunable...yet the merc one can be tuned by a few but it's a crapshoot a lot of the time...and without a redo on the fuel system prone to vapor lock...