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E15REIA fuel issue

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Tmjq0423

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I have a 1991 15hp evinrude. When running at high speed it starves for gas. To give a little history I have cleaned the carburetor and rebuilt the fuel pump. I’m pretty positive that is all good. I have to pump the primer bulb ever 10 seconds or so while running to keep it going. By doin so it runs great. I removed the fuel line going into the carb to see the fuel pumping. When idling it pumps out a 3-4 inch stream of gas but if I put it in gear and rev the engine the fuel pressure seems to decrease to the point it just runs out the end of the hose. I’m pretty mechanically inclined but this has got me stumped. I have also did a compression check and it has very good compression. Please anyone who can help me I would really appreciate it.
 
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This is a brand new tank. Also new primer bulbs and fittings. Did not change the hose. I will try that though. I am expecting an air leak somewhere. Just can’t seem to find it
 
Fuel pump is driven by crankcase compression + positive pulses and slight negative pulses.----Perhaps there are issues there or issues with fuel pump itself.----Looked at the valves in the pump ?----Is it the big pump or the wee square one.
 
It is the little square pump with the single diaphragm. The valves in the pump move freely by pressing gently with a screwdriver. The pulses you r talking about are from the compression and the diaphragm spring back and forth right
 
I had a similar issue with my 79 Johnson Javelin 100HP, replaced fuel pump, new fuel lines, filter, checked carbs but every time we took it out on the lake and put it to full throttle, it would bog down and eventually shut off, starving for gas. It would idle fine and run at slow speeds with no issues, the problem we found was what "johnnygjr" referenced above, the fuel line was collapsing. The fuel line was to small (or old) for the engine, and when throttle was hit it just collapsed the fuel line and that was the cause of the "bogging". Put a bigger fuel line on and sounds like a cat purring (loudly), and runs great. Hope this helps and good luck
 
I havnt noticed the hose collapsing but I am going to try a new hose and see if it helps. I had someone tell me there is a chance that the new needle valve may have been a little longer than the original. anybody had this experience before. I'm goin back into the carb to check that also. hopefully one of the two will work.
 
ok so I have tried a new hose. I have also went back in to the carb and made sure the throttle flapper is exactly horizontal at full throttle. while I was in the carb I made sure the float was set at level position while holding it upside down. here is a video of the fuel pump pressure while engine is running. in the video you can tell when I put it in gear and rev it up.

After watching the video I posted, can you tell me if the amount of gas coming out when it is put in gear looks like the amount that should be coming out?


https://youtu.be/GB3WEomowJo
 
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