help 30 hp 2 stroke dies after warm up

[matt88]

I recently purchased a used 30 hp 2 stroke tohatsu and have been having trouble with it. I was told the boat had been sitting for a year or two. When its cold it will start with minimal effort and runs ok until it starts warming up. It then starts losing power and dies. I have to back off of the throttle to keep it running. It is also very hard to turn the engine over after it warms up like its building compression. After forcing the motor to turn a few times it will free up and turn easier but the motor will be flooded out. I know I have some carb issues but can someone tell me why this thing is building compression like this after it warms up? thanks

 

[Mas]

Re: help 30 hp 2 stroke dies after warm up

Is the motor overheating?? Can you leave your hand on the head for a three count? The motor does not change the amount of compression...but it could bind with friction due to thermal expansion.

If your motor is too hot, test your thermostat and service your water pump.

MAS

 

[matt88]

Re: help 30 hp 2 stroke dies after warm up

thanks for the reply that sounds right because when the engine tightened up like that there was steam rolling off the block. It didnt feel hot but I didnt put my hand on it for just a second or two. I have a feeling though its getting hot due to a lean condition. The primer bulb stays firm but if I pump it it seems to run better. I probably have multiple issues with this thing. After it heated up it would run in neutral but cut out when I put it in gear. How can I tell if I have a blown head gasket? thanks for the help guys

 

[matt88]

Re: help 30 hp 2 stroke dies after warm up

ran compression test one cylinder reads about 120 psi and the other around 110. This is quite a relief I thought for sure that one of them were probably dead. I also pulled the wires off each plug and both cylinders are firing. Im planning on new spark plugs and a fuel filter but Im not sure how to determine if the water pump is bad. Can someone tell me if this engine has a thermostat and where its located? The model# is m30a. Im still fairly new to outboards and any help is appreciated,thanks.

 

[Wee Hooker]

Re: help 30 hp 2 stroke dies after warm up

First, you should see a "pee" stream comeing out of the engine cowling in the rear. IF you don't your WP or cooling system has problems that will cause SERIOUS damage if you continue to run it. Assuming you see the stream, here is another test.

Once it starts "dieing" , try spraying some 50:1 fuel mix right into the carb. If it perks up, it's fuel system related. ( An old windex/ household cleaner bottle will work in a pinch.)

I don't like the sound of that "Steam off the block" and "Hard to turn over" symptom. Sounds like overheating to me.

 

[matt88]

Re: help 30 hp 2 stroke dies after warm up

I fixed it! Filled a trash can with water and started inspecting the cooling system. Opened the thermostat housing and the water passages were bone dry. A mud dobber had worked his way in there somehow and blocked the hole next to where the thermostat sits. I poked it with a screwdriver put the housing back on and it works perfect now. Just took it to the lake to be sure and I cruised around for about 45 minutes with no problems. I think it still needs a fuel filter because at wot I had to pump the primer bulb a couple of times to keep it from cutting out but other than that theres no other symptoms. thanks for the replies. This site has been a huge help.

 

[Mas]

Re: help 30 hp 2 stroke dies after warm up

The water pump should be replaced every two to three years...and immediately if you do not know when it was last done. The water pump is really the "lifeline" of your motor.

MAS