7.4L 2001 2700 scr will not get above 3000 RPM

[cgheli]

Hello, I am new to the forum so hello everyone. I am new to boating and purchased a maxum 2700 scr 2001. It was fine for a few months and then the other day I was up on plane at 3200 Rpms and it just started bogging and came off plane on its own. Now it will not go above 3000 rpms. It starts to bog. If I back off the throttle it runs fine. It starts fine and idles fine. Anyone have this issue before? Any help would be great. I am a helicopter Mechanic but no little about boats. I was thinking fuel filter so I changed it and there was no water in it so my fuel source is good. Now it will not start... I assume the fuel filter that I put in needs to be full of fuel before I install it? I put it in empty. So if anyone has any ideas that would be great. Thank you in advance if you are able to help.

[seapuppy]

Hi and welcome to the zoo..I had this happen also...but for me they had a smaller canister type inline fuel filter down in the bilge from the tank to the spin on filter....that was clogged....so...since you replaced the spinon filter....that should be ok....but the other thing it can be is at the carb there is a screen or small filter that is usually in the base of the carb where the fuel line goes into the bowl top...that might be clogged....
another place to look is the pickup at the bottom of the tank.....careful to ensure that everything electrical is turned off.....finally....check the vent to the tank on the stbd side of the boat....if that is blocked ...it will create a vacuum and not allow gas to get pumped up to the carb....

let us know how it comes out..

SP :hello: irate:

[cgheli]

Thanks for the quick advice! I should have added that it was A 7.4 L MPI, no carb. could the plugged vent keep it from getting the gas it needs even when it is an injected engine? I will change it out as the one for the waste tank is plugged. I found that out when pumping my tank at the fuel dock and my wife says " Why is the tank getting sucked in?"

[seapuppy]

my last boat was an mpi engine and the canister filter was blocked...did the exact same thing..check the fuel line and follow it to the pump assy.....if there is no inline filter..then it has to be either the pickup or the vent...that's all there is that it can be..

SP :hello:

[cgheli]

Ran boat today. Started bogging again but not as bad. I opened the fuel fill cap to check if the vent is clogged and it ran fine! I can only assume the vent is clogged. But of course now when I started the boat up the alarm would not shut off. When I turn the key it tests fine. When it was at idle the alarm started going off. I checked the Temp and oil pressure both were fine. I was off shore so I started comming back and as soon as I started going the alarm stopped. When I put the engine in Nuetral at the dock after about 40 minutes the alarm started again. I revved up the engine, not in gear and the alarm stayed on then 30 seconds later when the engine was back at idle it stopped on its own. I checked the level of the lower unit and it is below the min line but there is about a half inch visable in the remote tank on the engine. I will add oil and hope that is it. Any thoughts? Anyone have this happen to them?

[Big Joe]

I've had that alarm before too. The system Maxim uses monitors temp, press and oil level in that lower unit. Not sure what the exact values are that make it trip, but this narrows it down anyway.

Sure wish Maxim put out an IETMS don't you? I'd settle for a NATOPS.

[cgheli]

Checked and filled the lower unit remote tank. It was not empty but I could see the probe that sets off the alarm. So far no more alarm. Thanks once again for helping this newbie. Yesterday I went down to the boat to clean it up a bit and then take it for a run, Another newbie mistake, once I started cleaning it was like opening a can of worms.I was there four hours and never made it out on the water. Going out today though!

[cgheli]

Update: I changed the cap and rotor and the sparkplugs and took her out and no bogging.

[seapuppy]

great...so all you needed was a tune up!!....thanks for the update!

SP irate: