1965 9.5hp evinrude dies at full throttle

[yostep]

This little beast runs aliek a champ for ever until you throttle all the way up. went across joe pool lake tuesday at half throttle without missing a beat but as soon as i would throttle up it would run only for a coupel minutes then die out on me like its not getting fuel. pumping primer doesnt keep it running as it bogs down. Any info would be greatly appreciated.

 

[Joe Reeves]

Re: 1965 9.5hp evinrude dies at full throttle

Assuming that it starts right back up, isn't seized from overheating, try pulling the choke out somewhat when that happens. If the rpms increase, I'd suspect that the carburetor needs cleaning.

If on the other hand, even though the engine will turn over, you need to wait awhile before it will start, check the spark plugs for water traces as a the head gasket may just be starting to fail, allowing water to enter at that high rpm.

 

[ezeke]

Re: 1965 9.5hp evinrude dies at full throttle

Very possible that the engine is overheating, so next time take the cover off and feel the cylinder head. You should be able to keep your fingers on it for at least a count of three.

For a while some of the aftermarket waterpump impellers were not very good. If you have not changed yours recently, I would do that. Also take the cover off the thermostat and see if the cooling circuit is clean.

It is possible that the float valve is sticking. That would prevent more fuel from getting in, but there is no reason for it to happen only at high RPM.​

 

[yostep]

Re: 1965 9.5hp evinrude dies at full throttle

Thank both of you for the extra fast replies. I'm taking it out this weekend so i guess ill do both of those things and get back with you. Once again thank you so much. With that in mind and it happens to be impeller and its over heating could i possibly have hurt it by running it for long periods of time at mid-throttle? I ran it straight at about half throttle for 25 min or so twice this past week. Would be greatfull for any insight?

 

[Joe Reeves]

Re: 1965 9.5hp evinrude dies at full throttle

If water is shooting out that large hole at the port (left) rear portion of the engine at all times, I wouldn't be concernned about overheating.

 

[yostep]

Re: 1965 9.5hp evinrude dies at full throttle

Ok so I just got back from the lake and tried pulling hte choke out a little bit and running it at high rpm and it did pretty much the same thing except with a little more chuga lugging. so i took the cowl off and felt it and it was cool enough to touch. Its still spitting water so i figure the impeller is good. When i took the spark plugs out there was a very little amount of brown liquid that almost looked like used oil in there but mainly on the bottom plug. let me know what other info i can give you if any to help me solve this. If it so happens to be a/the head gasket would this be somehting i could repair myself? I am very mechanically inclined and would think if i can rebuild a chevy motor i should be able to replace a gasket on a 1965 boat motor eh? Thank in advance for any help or comments.

 

[ezeke]

Re: 1965 9.5hp evinrude dies at full throttle

Before doing anything else, try running the motor up again with the cover off. The 9.5 has a tendency to pull exhaust gases into the engine compartment. There are several avenues if that is the problem.

And, yes, the cylinder head gasket is easy if the bolts are not corroded .

 

[yostep]

Re: 1965 9.5hp evinrude dies at full throttle

Thank you for the info i'm just curious as to if I should replace this head gasket before i run it again? If so it will be a week or more before im back on the water. Is there any secrets to changing head gasket and possibility of damage from running the motor like this. By chance could you tell me the torque specs on head bolts?. Once again i would like to thank you gentlemen for helping me through this. Guys have been awesome.

Sincerly J.Barnes

 

[yostep]

Re: 1965 9.5hp evinrude dies at full throttle

Thanks again guys for the help i just wanted to make sure i was ordering the right part from this site.

engine size:9.5 year:1964-1973 part#:18-2950

 

[ezeke]

Re: 1965 9.5hp evinrude dies at full throttle

That is the right number for the Sierra cylinder head gasket. The torque setting is 96-120 inch pounds. The sequence is as shown here:

 

[grid]

Re: 1965 9.5hp evinrude dies at full throttle

One other thing: remove the cover and accelerate in gear. If your shock mounts are worn, the choke will close as you accelerate, killing the engine. There's no cure for this other than throwing several buckets of money at it.

 

[yostep]

Re: 1965 9.5hp evinrude dies at full throttle

Ok so now I have replaced the impeller, head gasket, and fuel filter cap. I'm still having the same problem but it seems to have gotten worse. It wont let me get to full throttle at all before it dies. when i mess with choke while trying to slowly throttle up it does same thing. With or without cowl/hood on it does same thing. My next guess is to rebuild the carb and see what happens.Unless of course ya'll have any other suggestions, questions, or comments. Thank you very much for your help.

 

[Carbkid]

Re: 1965 9.5hp evinrude dies at full throttle

So what did you come up with? Did you ever get this motor running right?