de restricitng a 4 stroke mariner

stairliftoheaven

Petty Officer 2nd Class
Joined
Jun 8, 2004
Messages
113
good evening (its evening in london)<br /><br />I bought a 11' inflatable with a 13.5hp 4stroke mariner in spain a couple of years ago. The dealer told me that it was really a restricted 17hp but spanish law allows a maximum of 13.5hp due to local licencing laws. Now, i was reading the owners manual and it seems there are 3 models all different HPs but all have the same bore and stroke. When I serviced the engine the following season, I removed restrictor which sits between the carb and manifold; a 1/4" plate with a half moon shape in line with the venturi. The took it out on the water and the boat now jumps onto plane in a fraction of a second. The point of all this is that it now seems to be overrevving although I don't have a rev counter. After reading this gr8 forum, I reckon I need to find a higher pitched prop to keep the WOT revs down. Not sure about this though, any comments?? Also after removing the restrictor, do I need to change the jets in the carb as it may be runnign lea :confused: Any ideas on the subject much appreciated<br />thanks <br />chris
 

stairliftoheaven

Petty Officer 2nd Class
Joined
Jun 8, 2004
Messages
113
Re: de restricitng a 4 stroke mariner

oh yeah forgot to mention, have experienced what i think is prop ventilation as well since de restricting....
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: de restricitng a 4 stroke mariner

Moving to Mariner Troubles.
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Re: de restricitng a 4 stroke mariner

That's great info but you may need to richen the mixture now to prevent lean running. Compare jet sizes with the larger version.
 

FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: de restricitng a 4 stroke mariner

Before you get all excited get a "Tiny Tach" before you go guessamating....Jet size on restrictor plated outboards should remain the same with restrictor plate AFTER the butterfly...Restrictors DO reduce top STANDARD rpm of the motor. Of course the motor will sound like its reving more. Again as I said, get a "Tiny Tach" before you go out blowing wads of money guessamating.... :cool:
 
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