Evinrude 88 spl overheat warning system wiring

[JGra]

I have a new to me boat with a 1996 Evinrude 88 SPL on it. The motor seems to run good but have only had it out once due to a throttle cable that broke and did not get much of a test. It kinda acted like it may have been running a little hot but I am not too sure. I have always had Mercurys in the past. On them when I would get a steady alarm until the eng was started. I am wondering how the overheat system works on this engine, I get no bells or buzzers at all when the key is turned on. I dont even know if the boat was every equiped with one or it may have been disconnected. I know it has one temp sensor in each head but unsure what kind of signal they work off of. Do they put off a ground signal when the switch reachs a certain temp? I would like to add my own system and run seperate wires so I know they are working. The engine is a 1996 Sunbird Spirit 170. I have a manual ordered but have not got it yet. Can anyone help?

 

[DargelJohn]

Re: Evinrude 88 spl overheat warning system wiring

88SPL does have temp sensors in each cylinder bank. I believe they are ground signal, and complete the circuit at 195 degrees. The hot horn is in the control box. An easy way to see if the heads are overheating is to run the motor on water muffs. With the cowling off, let the engine warm up, and you should be able to hold your finger on each bank for a count of three. Or use an IR temp gun, should be around 140 degrees.

 

[boobie]

Re: Evinrude 88 spl overheat warning system wiring

Turn your key on, disconnect a wire going to a temp sensor on the block and ground it. If you hear a horn you're okay. If not you may have no horn or a wiring prob.

 

[JGra]

Re: Evinrude 88 spl overheat warning system wiring

Thanks, I worked on it some tonight. I found the two sensors at the cylinder heads, I tried grounding each of the sensors with the key on and got nothing. I looked under the dash and could find no buzzer. The boad has a hidden side control and from the best I can see there is no buzzer there. Rather than cut out all the wiring and tring to find the wire going up front (if there is even one) I want to run a whole seperate system. I already have a 12 volt buzzer from another old boat project. I am going to tie the 2 temp sensors together and hook it up to the ground side of the buzzer. I will then use a hot in run poistion wire to the positive side of the buzzer. Someone said to use the purple wire (tach ?). All this should work providing the temp sensors are good, which I dont know of any way to test. Does this sound ok. I dont like not having no overhear warning. I am going to replace the waterpump and thermostats due to the unknown.

 

[boobie]

Re: Evinrude 88 spl overheat warning system wiring

If you want to do it that way, sounds okay to me. Just make sure to check to new horn after installation.

 

[JGra]

Re: Evinrude 88 spl overheat warning system wiring

I have the engine wired and will run them to the contol panel. I ended up wiring them individually, each to a seperate LED light but both wired to the buzzer. This way if I do have a problem I can tell if the issue is coming from the left or right cylinder head. After I get everything wired I am going to ground each sensor wire to make sure its working. Doing good?

 

[boobie]

Re: Evinrude 88 spl overheat warning system wiring

Yes. Keep us posted.

 

[JGra]

Re: Evinrude 88 spl overheat warning system wiring

Just wanted to post saying the overheat alarm worked as it should. In fact it even went off the last time out. I was waiting in line at the boat landing and had been idleing for about 15 minutes and it went off. It showed left head overheat. I was in some shallow grassy water so I thought the intake might have got clogged. Anyway the water was pumping great so I decided to replace both the thermostates (pain in the butt) and found the left side thermostat broken in half. There was no way it was opening. I hope this fixes it, but the alarm did what it should have.