Only getting 3200 rpm on an aq260a

[bluecollerboater]

I have a 1985 Bayliner 23.5' ciera with an volvo penta aq260a and a 280 outdrive. Last summer i could get her to 30 m.p.h. but my tach didn't work. This year my tach works. I can get it up to 3200 rpm but only 25 m.p.h. This past winter I replaced the cap, rotor, coil, plugs and wires. So I am pretty confident the ignition system is in pretty good order. She runs well, solid no skips or hesitation. heats up to about 160 degrees. I am pretty sure I should be getting 4200 to 4400 rpm. What else should I look for? Could 1 or more of the parts I replaced have been bad? Thanks in advance for your help.

 

[Don S]

Re: Only getting 3200 rpm on an aq260a

Did you replace the points and condenser? Set the dwell, then the timing?

 

[bluecollerboater]

Re: Only getting 3200 rpm on an aq260a

Sorry. It has electronic ignition. And no I did not set the timing. I do not know how to do timing.

 

[bluecollerboater]

Re: Only getting 3200 rpm on an aq260a

I went to my boat today and set the timing at 8 degrees btdc at idle(600 rpm) and 30 degrees btdc at 4200 rpm(didn't like reving it that high) per the volvo penta manual. I took it out for a test ride and full throttle was 3500 rpm which is up from the 3200 i could get before . At the dock i could get 4400 rpm while not in gear. that is the max rpm that the manual says to run this engine at. So I think I need a new prop? Any ideas or comments would be appreciated. Does anyone know what prop a 1985 23.5' bayliner ciera with a volvo penta aq260a and 280 outdrive should have. I have no idea if the po changed the prop or it is stock.

 

[Don S]

Re: Only getting 3200 rpm on an aq260a

At the dock i could get 4400 rpm while not in gear. that is the max rpm that the manual says to run this engine at. So I think I need a new prop?

You check for prop rpm at WOT in gear on the water on plane and at proper trim. Not in neutral :facepalm:
Revving an engine in neutral is a useless test and tells you nothing.

Timing is only one very small part of the complete system. Check everything on the list I posted. And don't expect the problem to be some simple adjustment.

You need to do some testing.

 

[bluecollerboater]

Re: Only getting 3200 rpm on an aq260a

There are no points or condenser. The wot prop rpm i can achieve after setting the timing is 3500 rpm. What else should i test?

 

[Don S]

Re: Only getting 3200 rpm on an aq260a

Oops ........... I forgot to post the link on my original reply. :facepalm: Here it is.

http://forums.iboats.com/showthread.php?t=295070

 

[bluecollerboater]

Re: Only getting 3200 rpm on an aq260a

Thank you Don S. Your response makes a lot more sense with that list. I really appreciate your help.