1965 40hp Evinrude

[oregonmike]

Greetings,

Ok, here's hoping someone has some pointers...

Have a 1965 40hp Twin Evinrude, with a non-rebuildable fuel pump (tested per service book no leaks). Newer rebuilt lower. Turns over great, new spark plugs. Rebuilt carb with no leaks, holds fuel, electric choke works, fuel line build up pressure great, no water in fuel (tank cleaned and good about of new mixed fuel).

Won't start without placing fuel directly into area near choke, then runs until that fuel is burned then dies.

It seams to not want to suck up the fuel in the carb...

When last ran it and shut off (out in bay) it would need to constantly be re-primed to start even after being off for a mear few minutes. Now it won't start unless fuel is directly near choke.

First thought was carb, then we dismantle and rebuilt... No luck. Second was fuel pump, followed service book to test for leak in diaphragm and nada... Also checked fuel lines and cleaned tank completely, no avail.

Going in circles with only the thought of fuel issues...

Any ideas would be greatly appreciated.

 

[racerone]

Re: 1965 40hp Evinrude

The classic trouble shooting steps need to be done here.-What are the compression values ?------Will spark jump a gap of 1/4" or more.----Why do you say the pump is non rebuildable ?---Was the high speed jet that is screwed into the carburetor bowl removed for cleaning ?

 

[oldboat1]

Re: 1965 40hp Evinrude

yeah, first impression is that you have a fuel issue, but also sounds like you got your ticket punched troubleshooting carb and pump, so time to check for spark and compression (above). If you find that spark and compression is OK, you might simply test to see if the fuel pump is working by cranking the motor with the carb supply line disconnected (plugs out, as when doing compression testing, and fuel line into a container (glass jar a good idea, just to see if there if the fuel is clear of any debris.) But if the above checks out, I think it's back to the carb. for what may have been missed -- doesn't take much. Have to fully disassemble and soak all metal parts in solvent. High speed jet has to be removed and cleaned (solvent, small wire) along with all carb passages.

reference to priming to run sure sounds like a fuel pump issue. Squirting fuel into throat of carb to get it to fire (if that is what you are doing), if you know there is fuel at the carb, indicates to me that the jet is blocked.

If the '65 has a low speed needle, that will require disassembly for cleaning of all passages.

 

[kodibass]

Re: 1965 40hp Evinrude

try raising your fuel tank up above the power head to gravity feed the fuel, see if it will then start, goodluck .

 

[gm280]

Re: 1965 40hp Evinrude

If you can squirt fuel mixture into the carb and it runs, then ignition, compression, spark. timing and all those things are good. And I know you stated that you tested the fuel pump and rebuilt the carb, but one of those two is your problem still. I'd test the fuel pump like sated above by pulling off the fuel line at the carb and cranking the engine over. There should be fuel flowing out easily. If that works, it IS your carb. Buy a rebuild kit and take everything apart on the carb. Make absolutely sure all passages are completely open and clean. The jets (both high speed and low) have to be perfect also... Post your results after further investigations....

 

[F_R]

Re: 1965 40hp Evinrude

Squeeze the hose bulb till it gets firm, then remove the hex head plug from the bottom of the carburetor. A fairly considerable amount of fuel should flow out. That shows that the carburetor is filling. If the motor won't start and run for about half a minute or more after squeezing the bulb (carburetor filled as just explained) then the fuel pump has nothing to do with it. A full carburetor will run awhile if you were to completely remove the fuel pump.

I suspect the high speed jet (orifice plug) may be dirty.

Moreover, I suspect you have an ignition or compression problem. My favorite saying is "most carburetor troubles ain't carburetor troubles). Don't be fooled.

 

[racerone]

Re: 1965 40hp Evinrude

Agreed -------Most carburetor problems turn out to be something else.-----------Many folks pick on the carburetor as the problem.-------I think that is because electrical / ignition problems are confusing.--You can not see the electricity flowing in the wires.

 

[oldboat1]

Re: 1965 40hp Evinrude

well, easy enough to check compression and spark. Plugs are new, and presumably gapped to spec. Fuel pump pressure was checked (still would suggest the disconnected hose test as a very direct, simple test). If these systems are judged OK, then it's carb work again, which is more labor intensive. Ignition problems on the older models (this one counts) aren't too tough to remedy, but will be curious to see what you come up with.