1983 35HP Evinrude lacks acceleration

69triumph

69triumph

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Engine idles great. Engine throttles up with water cups on but lacks power under load. Engine will try to throttle up but dies back down and throttle has to be brought back to idle to keep from dying out. I have replaced the plugs, water pump and rebuilt the carb. The engine has low compression (about 115 on top and 100 on bottom) but with even that, shouldnt the engine run under full throttle, even tho with less power? Any ideas?
 
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tx1961whaler

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Re: 1983 35HP Evinrude lacks acceleration

First, check to make sure that there is spark on both cylinders. The compression issue might be as simple as changing a head gasket.
How were the carbs cleaned?
 
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Daviet

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Re: 1983 35HP Evinrude lacks acceleration

Does pumping the primer bulb when it is acting up help? The high speed orifice could be plugged up.
The compression should be OK. You could use a timing light to check the spark on each plug wire to see if you are loosing spark on one cylinder.
 
69triumph

69triumph

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Re: 1983 35HP Evinrude lacks acceleration

Carbs were completely disassembled (including removing pressed in caps) and sprayed with carb cleaner and all passageways blown with compressed air.
 
69triumph

69triumph

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Re: 1983 35HP Evinrude lacks acceleration

tx1961whaler said:
First, check to make sure that there is spark on both cylinders. The compression issue might be as simple as changing a head gasket.
How were the carbs cleaned?
Click to expand...

Spark is good on both cylinders also.
 
69triumph

69triumph

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Messages
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Re: 1983 35HP Evinrude lacks acceleration

Daviet said:
Does pumping the primer bulb when it is acting up help? The high speed orifice could be plugged up.
The compression should be OK. You could use a timing light to check the spark on each plug wire to see if you are loosing spark on one cylinder.
Click to expand...

Pumping bulb does not help. All passageways were blown clean on carb after i stripped it apart and used carb cleaner. Could be control box???
 
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