Why is my boat faster?

waterinthefuel

Commander
Joined
Nov 15, 2003
Messages
2,728
This is crazy, I know. I've been gone for a couple of years and while I was gone my father rebuilt my carb. I had moved the trolling motor battery to the back of the boat, along with the 6 gallon tank before I left with not much change in speed that I could see. Now that the carb has been rebuilt I am reaching speeds and RPM's never before seen by my little 28hp engine. It is literally screaming now, not to mention it starts much better than it ever did when it was new. Is it normal for a carb rebuild to result in a faster boat?
 

Mischief Managed

Lieutenant Commander
Joined
Dec 6, 2005
Messages
1,928
Re: Why is my boat faster?

Perhaps it was misadjusted for WOT and only opening halfway. Usually. a rebuild will result in bettre starting and idling due to gunk in the pilot jet but I suppose you may have had high RPM issues that the rebuild would correct. Have fun.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,130
Re: Why is my boat faster?

Is it normal for a carb rebuild to result in a faster boat?
Why Wouldn't It,..???......................
 

vipzach

Lieutenant
Joined
Feb 15, 2005
Messages
1,283
Re: Why is my boat faster?

Absolutely it could. The engine is now getting the right amount of fuel and air. It makes perfect sense. Tell your Dad thanks!
 

bidlimit

Petty Officer 2nd Class
Joined
Mar 1, 2003
Messages
102
Re: Why is my boat faster?

Another thing to consider: my '87 28 SPL was "detuned" from the factory; at full throttle the butterfly didn't open up all the way so I re adjusted it. Man what a difference, rpm's are right up there and I gained about 2mph. Not bad for a 10 second job.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,786
Re: Why is my boat faster?

What you are telling me is that your engine is no longer a 28 spl but now a 35 or 40. I am convinced that is how they build similar engines to get them to fit the hp curve....like a 28 and it's big brother are identical except one is lower hp.....yeah cause the factory detuned it and slapped 28 hp decals on it.<br /><br />My 2c.<br /><br />Mark
 

bidlimit

Petty Officer 2nd Class
Joined
Mar 1, 2003
Messages
102
Re: Why is my boat faster?

No, definitely not a 35 or 40, probably more like a 30. Or even more like what a 28 was supposed to do: <br /><br />RPM before plate adjustment: 4000<br />RPM after adjustment: 4700<br /><br />This is with the same prop, so therefore the motor was limited by the plate adjustment.
 
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