6hp evinrude only runs for a short time

This motor is new to me.
I bought it as a non runner,I stripped the carb and found the float cut off pin had been fitted upside down?It wasn't working the cut off valve in the bowl.
I fitted it back how it should be.
I bought a new petrol pump,but it came with the inlet and outlet pipe connectors in totally different positions to the original.(Had to make two new pipes to connect from the inlet pipe to the pump,and the pump to carb connection.
The bulb pumps up solid,and there is evidence of fuel in the air intake of the carb.
After setting the needle to the basic one and a half turns out,I managed to get it started.It was a bit slow to pick up at first,but then I was able to rev it freely.
It ran for a couple of minutes and then cut out.I can get it to start again after a couple of minutes,but it runs for a couple of minutes and cuts out again.
I suspect it is running out the fuel in the bowl each time.

Anybody got any ideas?

 

If it was a wrong pump, could you have inadvertently plumbed the in and out backwards? You'd probably be the first one to do that (this week... )

Is it mechanical, or does it rely on oscillating pressure - the latter are very prone to sticking of the one way valves inside the fuel pump - with just one OK they 'seem' to work if you suck and blow the ports but they wont pump. Even 'new' ones could have been sat on a shelf for 10 years so corrosion could be the issue.

if you disconnected the fuel and gravity fed via a pipe (Careful :! directly onto the carb bowl fitting, that would tell you lots.

 

The fuel pump is new,and a sierra,I got it by mail order from New York.
Because it is a modified pump I had to use longer bolts because the gasket and pump were slightly thicker,which is common practice I believe.
The pump fitted on perfectly,but the in/out connections were not in the same positions.I wondered if perhaps it has been assembled wrong at the factory.They are a pain to strip,which is why I bought a new pump.
If the float cut off pin needs adjustment I can handle that,but getting one of the carb manifold nuts off involves removing the pillar type starting pole,which is pre-sprung and a right pain to put back.
I blew through the pump before I fitted it,and I was able to blow through the pump from the fuel inlet end,but not from the outlet to carb end,which,according to the book is correct.
The pump is not mechanical,I think it is driven by pressure from the back where the gasket is.
Thanks for your reply

 

sounds like you have set the float level in the fuel bowl to low. What you are calling cutoff valve is the needle and seat. If the needle shuts off the fuel to early the engine will starve and stop. Fuel will flow into the bowl and the engine will start again and repeat the cycle. Adjust your float level as described in the manual. If the pump is the problem you can diagnose that by squeezing the bulb to see if that will keep the engine running. the fuel pumps on those small johnsons don't usually give much trouble.

 

Thanks for your reply.
I suspect it is the float level,it's a simple job to put right.Getting the nut off the carb manifold is a pain.The cord starter pillar has to come off to access it.I have had it off once and lost the pre-spring tension on it,you need two pairs of hands to sort it.
A 30 min.job can take 3hrs.
I suppose I will have to bite the bullet and get on with it.
Thanks again V

 

Can you get a flat blade screw driver past the starter to the nut. If you can just tap the nut loose with a hammer and screwdriver . I have done that before and put nut back with long pliers.

 

The other option is drop the fuel bowl off in place and adjust the float.

 

That sounds like a good idea,I'll give it a try.

The bottom bowl nut is not accessible because of the base pan.
From what I can gather,the carb needs to be upside down with the float level with the face of the bowl/carb for the setting to be right,which means to bend the hinge plate,it has to be accessible for the float to be got in and out.
I've set boat carbs and bike carbs over the years,but that nut on the carb manifold is what is making it awkward.
With a bit of luck,the screw driver and hammer method might work.

Thanks for your reply.V.