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7.4 L29 gen 6 454

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paul_rodgers

Regular Contributor
Hi guys I have a strange problem that I hope one of you guys can help me with. First I have rebuilt this engine everything new on inside, It is set right on in timing and starts at the turn of key. It will accelerate to about 2800-3000 rpm's and then it will sort of run into a wall and will hold that same rpm even with throttle wide open, it normally runs between 4200-4600 rpm's. But here is problem with it sitting in slip at marina and I push in the switch for throttle only it will rev past that 3000rpm's with no problem.. Is this normal? Thanks Paul
 
bt doctur could it be the prop?? he said throttles fine in the slip!!! sounds like what my boat was doing my problem was 4 stucked valves and cracked heads!!!!!!!!!!
 
rpm ever get above 3000 rpm, under load, since the rebuild? If no, make sure the throttle cable really opens the throttle completely when the control goes to the WOT position.
 
To answer all of your questions, 7.4 litre MPI L29 Gen 6 engine, Bottom of boat was just redone no build up at all, Has never gone over 3000 rpm under load but will go past that in slip. Timing is right on, New Plugs, Wires are new, pistons rings and all bearings were also replaced, I have not done an compression test since the rebuild, I guess I have done all the obvious, new water seperating filter, starts at the turn of key.. Just no higher rpm's could it be stuck in guardian mode?
 
I will double check that in the morning, I am kinda confused as to why it will not go past 3000 RPM's. I hope that it is something simple. Thanks
 
Plug wires are on correct all checked and while I was at it I checked timing, took boat out and same thing 3000 RPM's max. Boat planes out at about 2000 Rpm's, Just doesn't have any real power..the boat is a 2800 SCR maxum about 6000 lbs.
 
Gear ratio 2.0 it is the same drive that I had on it before and it ran well into the 4700 rpm's. I did do a compression test today. 1. 137 2. 135 3. 139 4. 143, 5. 137, 6. 135, 7. 136 8. 135, I am now leaning towards a fuel
problem, I have to get my hands on a fuel tester for the rail. I am going to check all the grounds and make sure all is clean and tight, At this point I am just shooting in the dark..
 
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