1972 Evinrude 50 HP 2 stroke fuel delivery issue.

[racerone]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

---" vacuum " hose----You do not get strong vacuum there!!!----Simply because the reed valves will open when piston goes to top dead center.

 

[Bosunsmate]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

Good photo, Looks like it comes from bottom cylinder.

 

[Bosunsmate]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

---" vacuum " hose----You do not get strong vacuum there!!!----Simply because the reed valves will open when piston goes to top dead center.

I would of thought the opposite, reeds close at top dead centre and open at bottom dead centre

 

[Sink/Swim]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

Ok Racerone, Do you think the issue is the lower crank seal? Is the seal causing the reeds to open at the incorrect time? Do you have any suggestions on how to diagnose where the issue is coming from?

 

[racerone]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

Reeds are controlled by crankcase pressures ( motion of the piston).---- If there is a hole in the crankcase or the bottom seal is completely shot then there is no change in crankcase pressure.----Take the time and visit U-tube , there are a number of tutorials that explain how this all works.--Some better than others.----When you understand this concept of crankcase compression , the trouble shooting will be so much easier !

 

[Bosunsmate]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

If you do a drop test on the top cylinder you will see if it the bottom cylinder is working enough to operate the pump properly

 

[Sink/Swim]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

Bosunsmate, Thank you very much for all of your suggestions. I found the problem last night! I kept searching on google , rewording my searches and I found a forum here on iboats.com. So when I replaced the reeds I also figured I would do the right thing and replace the intake gasket. Turns out there is a manufacturers defect on 1972-73 gaskets for my motor! There is not a pre made hole for the fuel pulse line!! Check it out... The gasket manufacturer is Interface #TN9004. Thanks again for the help. I will have the motor all back together tonight to test. Next lower unit seals.

 

[Bosunsmate]

Re: 1972 Evinrude 50 HP 2 stroke fuel delivery issue.

No worries, that is quite a fundamental defect!