2008 Tohatsu 6hp cuts out at higher rpm

[spitz351]

Hello all, I have a couple questions about my 4 stroke tohatsu and why it wont run properly

1) When I prime the fuel to the engine, it doesn't feel like its going to the engine because the primer bulb wont tighten (this one baffles me because I have tried multiple portable tanks AND fuel lines, bulbs)

2) After I do finally get fuel to it, I can start it, warm it up in idle and after about 3-4 mins of 1/2 to full throttle, it all of a sudden shuts off. I have found that while underway if I continue to pump the primer bulb, then the engine runs fine.....

To address what I have checked the following:
1) i have connected the engine to multiple tankes and lines to see if the issue was outside of the engine.
2) Taken off/apart the carb and thoroughly cleaned
3) replaced the fuel filter and inspected fuel lines.

I've reached my knowledge of these things and how to diagnose and remedy. I'm wondering if its a fuel pump issue??

 

[pvanv]

Re: 2008 Tohatsu 6hp cuts out at higher rpm

Year is no matter. I assume you have a MFS6B... If the fuel pump was leaking, you might have a soft bulb... and the fuel would go into the crankcase. What method did you use to clean the carb?

 

[spitz351]

Re: 2008 Tohatsu 6hp cuts out at higher rpm

Year is no matter. I assume you have a MFS6B... If the fuel pump was leaking, you might have a soft bulb... and the fuel would go into the crankcase. What method did you use to clean the carb?

Yes, that is my model #. I took the carb off, took apart, cleaned the ports and did the dip although it looked meticulous anyways. It just seems so strange that I can idle the engine fine and run it fine at wot as long as I'm priming the bulb periodically.

 

[Sea Rider]

Re: 2008 Tohatsu 6hp cuts out at higher rpm

Have you tried a new original fuel line ? works miracles on fuel related issues of that kind, could also check fuel pump diaphragrms for wear, fabric deterioration, etc.

Happy Boating

 

[pvanv]

Re: 2008 Tohatsu 6hp cuts out at higher rpm

If it runs better when helping the fuel along with the primer, then you are not delivering enough fuel with the pump alone. Could be drawing air, not drawing anything, or dumping the fuel into the crankcase. Check the inlet needle in the carb, and check the fuel pump. The MFS 4/5/6 can run on gravity alone, so if in doubt, bypass the fuel pump, mount the tank above the motor for the test (maybe have a helper hold it up if needed), and see how that works out.