Tohatsu 5hp - Engine stalling when put in gear unless in a "sweet spot"

[griffinburd]

Tohatsu 5 HP, 2 stroke. 1997.

Carb was rebuilt and cleaned, water pump replaced, spark plug replaced recently. Compression was good at that time.

Rode the engine at full throttle for about an hour, fished for about 45 mins, and was riding it back at full throttle. After about 20 mins engine kicked up like it had hit something and immediately died. Was in deep water, thought I had hit a log or caught a crab trap, no evidence of anything on visual inspection.

In neutral it starts in a single pull and has the full range of RPMs and throttle response.

When putting into gear it will instantly die unless I very quickly find a sweet spot of half choke/half throttle and then it runs rough at barely above idle speed. More throttle or less throttle causes it to stall.

As I was limping the boat back to the dock I noticed that the rpms started climbing to where they should be at half throttle and then I was able to bring it up to full throttle again. I had to back off to avoid some wake and it went right back to having the same problem. When putting the boat in reverse I've found that it's the exact same "sweet spot" and about the same RPMs.

 

[Sea Rider]

Welcome to Iboats,

Seems an electrical condition, will need to make an electrical component troubleshooting. OB's usually run OK at neutral and begin to miss when geared at load, that's when full electrical power response is needed. Start checking all grounds to be immaculate clean and shiny.

Happy Boating

 

[pvanv]

Could be, but probably has some crud sloshing around in the carb.

 

[Sea Rider]

That's a 11 year oldie, either one could be the culprit. Soak carb again in carb dip for some hours, remove all plastic, rubber components before soaking. Check if running good at load. If same, sureley a bad electrical condition.

Happy Boating

 

[pvanv]

Luis, the fact that he must use partial choke indicates a fuel issue.

 

[Sea Rider]

Paul,
If Ob was running good for an hour without issues due to a good initial carb clean, don't think there's still crud sloshing around inside carb ? if it's fuel related could be a fuel pump failing issue, tanks could be dirty and clogging internal fuel mesh filtes when carb demands fuel as well.

BTW, which tank vere you using when having those mentioned issues. Internal or external fuel tank ?

Happy Boating