1980 Suzuki DT 25 seizes up

[seandosmith]

I was recently given a 1980 Suzuki DT 25 engine that had not been run in 15 years. Without replacing anything, I got it started and ran on a lake for about 30min at half throttle with no problems. A week later I ran it on the lake again, and after reaching full throttle, I began to slowly lose power (over a period of 1-2 minutes), until it died. When I tried to crank on it, everything was seized up. I waited for about 10-15 minutes and tried pulling again, and got it to turn over. Trying to figure out what the problem might be. My thoughts are cooling system, but I don't know where to start. Thanks for any help.

 

[99yam40]

Re: 1980 Suzuki DT 25 seizes up

I was recently given a 1980 Suzuki DT 25 engine that had not been run in 15 years. Without replacing anything, I got it started and ran on a lake for about 30min at half throttle with no problems. A week later I ran it on the lake again, and after reaching full throttle, I began to slowly lose power (over a period of 1-2 minutes), until it died. When I tried to crank on it, everything was seized up. I waited for about 10-15 minutes and tried pulling again, and got it to turn over. Trying to figure out what the problem might be. My thoughts are cooling system, but I don't know where to start. Thanks for any help.

You might want to check to make sure the lower unit has not locked up, only seen it once but it did happen.
If that is not it then you probably where running lean fuel/air mix and caused piston/cylinder problems

 

[seandosmith]

Re: 1980 Suzuki DT 25 seizes up

I took the lower unit off, checked the water pump impeller, and opened up the gear box. Nothing appeared wrong. I took some fishing line off my prop shaft, and re-greased some stuff, and put new gear box oil in. When I flush the cooling system, it pees nicely, but I did notice beads of water coming out of one of the gaskets on the engine. Thought maybe it wasn't able to create a vacuum because of this. Next I will check the fuel lines and pump. Does anyone have any other ideas of what should be done to this engine after 15 years of storage? Thanks.

 

[seandosmith]

Re: 1980 Suzuki DT 25 seizes up

Turns out my thermostat was bent, and clogged with a ton of exhaust particles and silt. Going to get a new one and put everything back together and try again. Any other suggestions on what maintenance or replacements I should make on a 2-stroke suzuki engine that has been poorly stored for 15+ years?

 

[mphelle8vld]

Re: 1980 Suzuki DT 25 seizes up

I would check the compression to see if the rings are still able to function after sticking the pistons.