wot or is it

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
i took the sunbird out today to test the carb rebuild and she starts fine and idels great at what sounds like 800 rpm jus short of dieng but tach reads 1200 rpms engine shifts in and out of gear ok tries to stall a little as it goes in but recovers on its own take up to wot slowly carb plates are all parrelel and in sinc<br /><br />but the boat planes out and skips across the water at or near 30 miles an hour at 4800 rpm max but the motor sounded great as if it was wot <br /><br />is this good for the 1985 70 hp evinrude or should i get more like 5500 and take flight <br /><br />could this be the result of prop damage i have a few good dings and dents in mine <br /><br />i know this is alot of little questions but to say the least having it running this good has got me riled up a little :D :D :D
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: wot or is it

Sounds to me, and I am no expert by any stretch of the imagination, like you missed some junk in the carbs when you rebuilt them. Guessing in one of the low speed jets. If your prop is really bad then it might be time for a new one or at least a rebuilt one.
 

npd4432

Chief Petty Officer
Joined
Apr 18, 2006
Messages
468
Re: wot or is it

I believe the max RPM for that motor is 5800. What pitch prop do you have??<br /><br />I have a 1983 75HP with a 13 pitch prop and the motor WOT is about 5700-5900.
 

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
Re: wot or is it

prop picth is 10 the boat palains out and tryes to skip to the point of cavitation at 4800 i dont really think it could handle any more without becoming an airplane 5800 wow that will be moving is there a chance that the tach is just wrong is ther anything there i can check <br /><br />this is a 15 ft sunbird spl 150 if it is true <br />4800 rpm is this going to be to much motor for this boat or do i just need to work on the trim and prop to get the best results<br /><br /><br />thanks again vader
 

KYHunter2

Chief Petty Officer
Joined
Mar 20, 2006
Messages
512
Re: wot or is it

If your tach is right . You are lugging your motor . I believe , your recommended WOT , rpm's is 4500-5500. That is factory specs. But most of the experts , recommend 5800-6000 rpm's.<br /><br /> Your motor, should have it listed on a plate on the mounting bracket.<br /> But, 4500 is definately too low.<br /> <br /><br /> As far as too much for your boat . That should be listed on the capacity info. plate on it as well.<br /><br /> Good- Luck,<br /><br /> KYHunter :)
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: wot or is it

I doubt your Tach. is correct. Check the settings on the back of the Tach. Should be set to "6" pulse. The reason I say this is I run a 14" X 11" pitch prop on my toon with my 90' 70 HP and turn right at 6000 RPM's. Your 15'er should be running a higher pitch prop than I am, as it's much lighter. If anything, you are turning over the limit with that prop. Either that, or it's not really a 10" pitch prop...Check both and let us know...
 
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