Tohatsu 25hp irratic running

[Flagler beach]

I just purchased this 1991 14 foot Ash craft with a 2stroke 25HP M25c2. This boat has been garaged all of it's life and looks great Problem is it has been not run in about 7 years. Got it running easily. It needed an impeller and it was ready to run. Took it out and it ran great! The engine ran strong. After about 10 minutes the engine shuts down and won't restart. I finally figured it out, the fuel line came loose from the tank. One of the females on the boat was nervous so I took her back to the dock. Brought the boat home for a few weeks. Got ready to take it out again and did a quick start at home and all was great. Put in in the water and it just didn't want to run. If you could get it going it would do okay a WOT. Now it won't idle and is hard to start. Took off the carb and cleaned it out. It had dried up gunk in there. I did swap the plugs out on the first trip. Now I am messing with the mixture screws and so on. Sometimes it will sit and idle great for 10 minutes and then get rough. Try to speed it up and it will cut off and hard to restart. It sounds like it is running out of fuel but the bowel is full. The squeeze fuel ball seems firm but not hard while running, is this normal. I am at wits end and think about getting a new fuel line and carb just because I am out of ideas. Any help would be appreciated.

 

[TOHATSU GURU]

Re: Tohatsu 25hp irratic running

The bulb should be firm...Chances are you have a fuel system problem, probably the carb, but anything can cause the problem you are describing.

 

[Sea Rider]

Re: Tohatsu 25hp irratic running

Welcome to Iboats,

Is engine missing at wot ? Or it's just missing, shutting engine down at idle ? Is fuel tank internal mesh filter, fuel lines, fuel pump internal housing and fuel filter inmaculate clean ? When engine is sufficiently warmed up and backing throttle to idle, does engine drops dead ?

Happy Boating

 

[Flagler beach]

Re: Tohatsu 25hp irratic running

Welcome to Iboats,

Is engine missing at wot ? Or it's just missing, shutting engine down at idle ? Is fuel tank internal mesh filter, fuel lines, fuel pump internal housing and fuel filter inmaculate clean ? When engine is sufficiently warmed up and backing throttle to idle, does engine drops dead ?

Happy Boating

Right now I am trying to keep it running in a trash can. It usually will not idle. Once it starts it will run a while at fast idle and then just quit. At times it will not idle at all. The tank is a 6 gallon portable, I have not replaced or cleaned the filter. It shows gas all of the time. And yes when warmed up and backed down the throttle to idle it dies (usually). To me it seems like it is starving for gas. I did put a carb kit I it today and it is the same thing. No change. Is it possible for the filter to be causing me an issue? It does appear to flow fine when I test it by removing the hose. I have even run the engine with the hose to the carb off just to watch it pump fuel.

 

[Sea Rider]

Re: Tohatsu 25hp irratic running

Remove carb's fuel hose entrance, place a container at hose end, open tank's air vent, prime bulb fully several times. If you have any sligh obstruction inside fuel lines, this should clear it completely. If you never haven't emptied your fuel tank, do it now, turn it upside down and remove all fuel, you'll be amazed what you can find there. Have you cheched gas pump internal diaphragams ? Remember that horse is an oldie...

Have seen guys fingering the whole engine, inclusively changing parts with no avail just to find as last option that their fuel tank was completely filthy, one should always start with fuel tank following gas circuit to carb entrance. If all related fuel circuit and carb is in proper order, you could have electrical issues...

Happy Boating

 

[Flagler beach]

Re: Tohatsu 25hp irratic running

Remove carb's fuel hose entrance, place a container at hose end, open tank's air vent, prime bulb fully several times. If you have any sligh obstruction inside fuel lines, this should clear it completely. If you never haven't emptied your fuel tank, do it now, turn it upside down and remove all fuel, you'll be amazed what you can find there. Have you cheched gas pump internal diaphragams ? Remember that horse is an oldie...

Have seen guys fingering the whole engine, inclusively changing parts with no avail just to find a last option that their fuel tank was completely filthy, one should always start with fuel tank following gas circuit to carb entrance. If all related fuel circuit and carb is in proper order, you could have electrical issues...

Happy Boating

Thank you for your suggestions. I had already started with new fresh fuel. After all of my frustration I slept on it and decided I would pick up new spark plugs. I had already changed them when this issue began. Anyhow, I put the new plugs in, hit the key and it fired right up and idled. The idle was a touch high so I turned it down. Shut it off and restarted. It is running perfect. Revved it up and it is so smooth. I was just about ready to pay to have someone else fix it. I have never done that before and I am thankful that I can still say that. Thanks again to all that offered suggestions.