I decided it was time to boost the speed of my 2000 Mariah Z302 which came with a single 7.4 MPI (310 HP) paired up with a Bravo III. I chose to do that by adding a Procharger SC unit with 5 PSI boost. After getting the thing installed, and pushing my props from 28 to 30 pitch, I took it out for the first test run. Once I got it on the water, I could tell right away that there was much more power and I came out of the hole faster even though I had larger props. All was well until I hit 4500 RPM at which time the engine started to stall and the exhaust gas got very hot. I could not imagine hitting the rev limiter at that low RPM, but after looking at the factory info on the top of my engine, I saw that the factory setting was for 4200 too 4600 RPM. It was then recommended for me to get my ECU re-programmed to solve this issue. The factor ECU was a FE28. I sent it off to have it re-programmed (several times, but that is a different story) and now things are worse. The Engine is cold starting (but something I can live with), but I cannot open the throttle all the way open without the engine starting to studder and then I get an engine alarm beeping at me. This happens both right out of the hole or if I just ease up the RPM until I hit around 4400 RPM. I am also noticing that the engine is now running very rich as everything is getting black. After two weekends of running like this, I had to change the oil due to dropped pressure and my noticing that I smelled gas in the oil. Has anybody else experienced anything like this or can offer any help? Thanks, Dave

First thing you should not have done is Procharge a 7.4 MPI. It has cast pistons that cannot handle the heat and any long term reliability is unlikely.

I think the rest of your issues revolve around ecu programming.

Hi

I thought many people have procharged their cast piston 7.4mpi's without issues in the past?

regards,

Richard

Where are you located?

You need a efi expert to tune your boat on the water,pure and simple. Depending where your at find someone willing to do it,install a bung in your manifold for a 02 sensor. In mich we use Tyler Crockett,he tuned my procharged boat on the water and it runs excellent,Smitty

I am located close to St. Louis MO.

You will get gas in your oil, it's caused by the blower and blow by. You'll need to change your oil often, like 15 - 20 hours. How amny hours were on the engine before installing the blower?

You really should be cautious with the 7.4 the pistons and crank are cast, not forged.

The previous owner of one of my boats ran a 7.4 for 3 years with a Procharger with no problems.

Kirk

Who is setting up your ecu? sounds like your too fat at idle and leaning out up top. tuning is critical, my boat couldnt idle 5 minutes without fouling the plugs, got the ecu set up right and its been great since. Dont give up it will work out.

Send your ECU to Arizona Speed and Marine they will take care of all of your issues and they have some great people down there to work with. Call down there and talk to a guy named Jim, ask him your questions and he will give you some straight answers.

It sounds as if you fuel pressure regulator gain is not set up properly. The fuel pressure may be but the gain rate to full psi may need tweaking. Procharger sells the regulator adjustment kits. I also have or can get you them as I am a distributor.. Also despite what others may say @ 5psi you should not have had to reflash the ecm on an otherwise stock unit for it to run properly.. I too have seen a bunch of hrs on procharged stock engines.. The key is not to be abusive and make sure you pamper it with services early ..

Jamie / Lakeside