Motor will not rev past 3k rpm

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lindsey

Cadet
Joined
Nov 22, 2009
Messages
26
I was in the boat yesterday it was running fine all day then it started hesitating when i would get on step up to wide open throtle. Then it cleared up.I then slowed the boat to a stop checked my fuel tank to see if i was running out gas everything was good.Try to get back up on step and the motor would not go past 3k rpm. The motor idles fine starts right up and will rev up fine with the cold start lever. Its a 1973 evin 85 hp.
 
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jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: Motor will not rev past 3k rpm

Try choking it, if that gets the rpm up (in gear not in neutral) then you might think about rebuilding carbs with new carb kits,

and do you have a water seperator, we need them now.
 
L

lindsey

Cadet
Joined
Nov 22, 2009
Messages
26
Re: Motor will not rev past 3k rpm

I tried that trick with no luck. The carbs where just rebuilt and all the fuel lines replaced.link and sinc where done to recentily. I'm thinking maybe water in the fuel or trash in the high speed jets because it idles fine starts on the first crank and i can rev it up with the cold start lever with no problem.
 
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steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Motor will not rev past 3k rpm

Did it cut out like you turned a switch?Maybe your loosing a cylinder.Check the spark.
 
honald112

honald112

Seaman Apprentice
Joined
Nov 8, 2009
Messages
46
Re: Motor will not rev past 3k rpm

I was having a similar issue on my 75 115 Rude. What was happening was the 1 and 3 coils would cut out. It would start fine and the warm up bar would bring it to 4,000 rpms, but in gear i couldn't get over 3000. I cleaned up the grounds on the coils and also the connections in the power pack. Make sure your battery is good too.
 
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jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: Motor will not rev past 3k rpm

lindsey said:
I tried that trick with no luck. The carbs where just rebuilt and all the fuel lines replaced.link and sinc where done to recentily. I'm thinking maybe water in the fuel or trash in the high speed jets because it idles fine starts on the first crank and i can rev it up with the cold start lever with no problem.
Click to expand...

You mean it will rev up with no load?
could be a cyl not firing.

Draw some fuel and leave in a glass, watch for water seperation after a couple of minutes.
 
L

lindsey

Cadet
Joined
Nov 22, 2009
Messages
26
Re: Motor will not rev past 3k rpm

well i found the problem.it was a very tiny piece of rubber from one of the fuel lines blocking one of the high speed jets go figure.
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: Motor will not rev past 3k rpm

Thats all it takes to melt a piston too if you run it all day WOT.
It pays bigtime not to assume anything.
 
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