1991 evinrude 48 spl surging

[petrey39]

My motor is surging only when the motor gets hot, or warmed up. The motor runs great until then. I have rebuilt both carbs., and there is no fuel problem that I can tell. The spark plugs are new. The ignition coil is the original but doesn't have any cracks. The spark plug wires are in pretty bad shape. Any ideas of where to start?

 

[tashasdaddy]

Re: 1991 evinrude 48 spl surging

plug wires could be arching and grounding to the block. late evening run the motor on muffs, and watch for spark jumping for the plug wires. also when was the water pump last changed, could be almost running hot.

 

[petrey39]

Re: 1991 evinrude 48 spl surging

As far as I know it is the original water pump. Would the motor surge if it was running hot? Is there a sensor on the motor to detect the motor running hot? Also the motor does seem to get unusually hot, but since I am a first time boat owner I don't know how hot it is suposed to get. I don't have a temperature gauge on the steering column.

 

[tashasdaddy]

Re: 1991 evinrude 48 spl surging

it shoudl run between 140 -160* you should be able to put your finger on top of the block and hold them there for 4 seconds, with out undue pain. you could also have a fuel line leak, air leaking in.

 

[petrey39]

Re: 1991 evinrude 48 spl surging

I dont' think the fuel lines are the problem. I can see gas going into the motor from the carbs. and they seem to be putting out equal amounts when the motor starts surging. The motor is definetly getting too hot, I cant hold my finger for more than a second.

 

[tashasdaddy]

Re: 1991 evinrude 48 spl surging

time to find out why, does it have a constant strong pee steam? if not it needs a water pump kit. if it is getting hot, the motor may be trying to sieze. you need a service manual, > http://www.outboardbooks.com/index.cfm?fuseaction=boats.main&manufactor=evinrude

 

[petrey39]

Re: 1991 evinrude 48 spl surging

No the motor does not have a steady pee stream. I have to get it up to really high rpms before it starts peeing.(doesn't pee at idle). I'm going to replace the water pump, ignition coil, and spark plugs wires.