Suzuki DT 75 Ignition Box Question

[yader84]

Hey all,

I was out on the Columbia River today and my outboard went ka-put. It's a 1987-89 Suzuki DT75. The engine was incredibly hot when I pulled the cover off. I found a piece coming from the ignition box on the side of the block and connecting into the engine itself on the top side. Two screws hold it in place. It was completely melted, beyond recognition. From what I could make out there was a straight piece of metal protruding from it into the engine, about the thickness of a pencil.

Does anyone know what this piece is? Any clues on what could cause this to happen? Why would the engine be running this hot??

Thanks for your help!

 

[99yam40]

Re: Suzuki DT 75 Ignition Box Question

Lack of cooling water or bad thermostat will cause over heating.
If it got hot enough to melt things, it is not a good sign for the internals of the motor.
Was it showing water at the indicator?
Have you tested your alarm system lately to make sure it funtions?
Have you changed the water pump and tested the thermostat or replaced in the last few years?

 

[yader84]

Re: Suzuki DT 75 Ignition Box Question

Unfortunately this is my first boat so this system is completely new to me. I've had it out three times already for about 7 hours total. It has run like a top so far. No issues whatsoever.

I'll put the things you mentioned on my to check/replace list.

When we first started out last night the launch was very shallow. Maybe 3ft of water in some places. We went through some weeds at one point and I'm thinking that perhaps some of them were sucked up in to the water system clogging it and causing it to overheat. It ran for a good 10 minutes after the weeds at low speeds.

Once we were into open water I gave it some gas, got up on plane, cruised around for about 2 minutes and then it felt like the engine began to lose gas. I wish I had looked back and checked if there was a pee stream, instead I was focusing on the gas system. I know I had a stream to start but I don't know if I had one to end.

First thing to do this morning...check if the engine seized and figure out what that piece is that melted.

 

[yader84]

Re: Suzuki DT 75 Ignition Box Question

Crank turned, tried to start the motor and it started just fine. The hole that the melted piece fitted into I semi patched with a piece of metal just to keep the elements out, by no means a tight fit, just a covering. When I started the engine I got a pee stream and lots of water coming out of the covered hole where the melted piece fit.

Anyone know what this piece is?

It has two wires going into the I.C. Ignition box. I pulled off the cover and see where they went. They went to nowhere. They were disconnected completely. I did manage to find two loose ends and match the wires. So now the question. What is this little piece and what type of sensor is it?

Thanks all!

 

[99yam40]

Re: Suzuki DT 75 Ignition Box Question

Post a picture or look it up on parts breakdown web site.

http://www.yamaha-motor.com/outboard/parts/home.aspx

 

[yader84]

Re: Suzuki DT 75 Ignition Box Question

The part is the cool water temperature sensor. Got a new one for $50.

New problem, blown out head.

Thanks for your help!

 

[stylesabu]

Re: Suzuki DT 75 Ignition Box Question

I have a complete dt 75 i bought as a back up for mine. I was told it ran but stalled. i have a head if you need it, may be its just a blown head gasket.