350 MAG MPI slow and getting slower

[Northern Baja]

performance of my 95 baja as always been a little disappointing, but recently it gotten worse. The engine starts instantly, idles great, a little slow getting it up then tops out at around 4000 rpm. My spare prop is a smaller pitch so I put it on as expected it helped getting on plane but the top end stayed around 4000. It doesn't seem to be running rough. I have noticed my temp is up slightly but not over heating. no smoke at any time.

Last year with very similar symptoms I replaced an inline filter just prior to the fuel logs and it totally resolved the problem. So I did the same this time but it had no effect.

To me sure acts like the fuel pressure/flow is low. What checks would you be thinking of. What are the common points of failure?

Thanks!

[tommynitro]

Northern,

Sounds to me like you do have a fuel flow delivery problem. Check for pinched off supply line from the tank, through the rear bench bulkhead and then to the spin on fuel/water seperator. If you havnt replaced those already I would recommend that you do so, at least every year. The fuel demand from the engines goes up drastically over 4000 rpms and it sounds like the engine isnt getting adequate fuel flow to make the rpms needed. I have had some boats form the factory like that that had a pinched off supply line to one engine and would run great up to around 4000-4200 but would start dying off after that, just not enough fuel flow.

Check that out and let me kow what you find...sorry it took so long to get back to you, I check the main board and the smae thread was up there for a while so I didnt check this section specifically....my bad!

[Saleen367]

Northern Baja,

If you can do a fuel pressure check. A fellow boater of ours also had this problem and it ended up being his fuel pump and his boat had only 28 hrs on it.
Also check your flame arrestor and make sure its not dirty or plugged up with dust, dirt or gime.
This all sounds like a fuel or air starvation problem.

Good luck

[pimpin502]

my buddy just went through this w/ his baja luckily and i mean luckily, they had to replace all of the injectors hope thats not the case, but his were defective from the factory, hope u get it fixed!!! :roll: