starboard engine loses power when planed around 3200 rpm.


R

Rick

New member
My 07 31 pc w/6.2 Blll lost power at about 3200 rpm on starboard side. Was on plane for maybe 5 min before the rpm began ocillating between about 2800-3200 rpm. You could feel the power drop and surge then drop again after 30 sec or so I came off plane and it ran fine at about 1400 rpm but after a half hr I tried to plane it and just as it planed out it started doing it again.
Has anyone experienced this? I plan to change the fuel filter and see if it could be the problem but it definitely seems like it is not getting enough fuel when running faster
Any suggestions??
Thanks, Rick
 
I had a very similar problem. Engine started to oscillate around 2800 rpm, but was ok at about 1600 and lower. I tried the fuel filter 1st, obvious choice. The problem ended up being the MAP sensor. You'd probably need a code reader to verify this, though.
 
My 2007 37PC acted similar when it was telling me it wanted new plugs. Engine won't run over a certain rpm. Plugs didn't look bad when i replaced but it did fix the lack or rpms and rough running. I put a little over 150 hrs on it in the 7 years i had the boat and replaced the plugs every 3 yrs. My buddy and his boat was exp the very same thing i was in the same 3 yr intervals. Might give it a shot.
 
Changed plugs one yr ago when replacing manifolds and risers and have had no issue until yesterday. Just acts like it is running out of gas until I lower the speed to below 3000 rpm. So I go off plane and run at 1200-1400 rpm and no problem. It does not spit, sputter or backfire...just drops power and then lunges back up and then drops again until I lower rpm.
 
Is there an anti siphon vavle at the fuel tank pickup? Where the hose connects to the fitting on the fuel tank. Ther is a small fitting with a check ball in it.. This was my issue but was on mechancal fuel pump.

search for my post in engines
 
One more step before the fuel hits the anti siphon check valve , the pick up tubes
My 2006 31 PC , Formula cut the tubes ( its a plastic tube ) longer then the bottom of tank and they where kinda bent and at top of fitting ( hose barb fitting ) it started sucking air
 
Rick said:
Changed plugs one yr ago when replacing manifolds and risers and have had no issue until yesterday. Just acts like it is running out of gas until I lower the speed to below 3000 rpm. So I go off plane and run at 1200-1400 rpm and no problem. It does not spit, sputter or backfire...just drops power and then lunges back up and then drops again until I lower rpm.
Click to expand...

Either lack of fuel or knock sensor. Check the plugs again and see if they are anything other then a tan color. If your engine is sensing a knock it will retard the timing to save the engine. Otherwise get a fuel pressure gauge and see what it is at the Schrader valve on fuel rail.
 
Had the exact same problem and it turned out to be the distributor cap. Check and see if there is any corrosion in there.
 
I dont think that a 2007 has a distributor. should be individual coil packs with a crank sensor.
 
All In said:
One more step before the fuel hits the anti siphon check valve , the pick up tubes
My 2006 31 PC , Formula cut the tubes ( its a plastic tube ) longer then the bottom of tank and they where kinda bent and at top of fitting ( hose barb fitting ) it started sucking air
Click to expand...

YES!! Check your pick up tubes. My 2007 31pc, same thing, pulling air at the barb on both tanks.
 
I would not totally dismiss a bad plug...one bad plug is very hard to detect...just saying, it could be that simple (and painful to check).

I've had multiple plugs "blow" for no reason within a year of being good.

However the 6.2 USUALLY don't blow plugs like the 496's.

I tend to agree with the others that it is fuel related.

I crazy test might be to get some fuel hose and temporarily re route to see if it follows the fuel house...other option of course is you might need to put a computer on it to see what is going on.
 
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No. Have a mechanic coming next week. Pickup tubes were fine. Thinking it could be hi pressure fuel pump failure.
Will post what I find out.
 
Wow...I started this thread a yr ago and just now am finding out what the problem was.
2 mechanics and almost $1200 in labor later it was a clogged fuel screen underneath the cartridge fuel filter! A flipping $40 part!
I now have new filters, hi and lo pressure fuel pumps and a new pickup tube! But boat runs great again...that's all that matters.
Thanks for all the suggestions.
 
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