'89 Evinrude 90HP question on temp sensors and alarms

[RickM101]

Hi All, New to the forum. I have tried to search for the answer but no luck so I apologize if this is redundant... I am trying to get the boat ready for the season. Problem I have is that it been very hard to get it started but this past weekend I got it to start but would only stay running at hi rpms 5000+, and at that the alarm would start going off after 10-15 seconds, a lot of fast beeps and then constant. Then the engine would seem to slow down and eventuall stall. Now when I say it was running it never ran more than a minute and nothing was hot to the touch. I have read all the stuff on the VRO2 and will probably disconnect it and start mixing fuel as that could be one of the issues. So questions are:
1. Could running the engine for such a short period cause it to over temp if the VRO was not pumping oil and cause the constant alarm?
2. Does it sound feasible that the fast beeps was the VRO(no oil) and then constant alarm (over temp)?
3. Would this significantly damage the engine?
4. I see 3 tan wires going to the heads (temp control wires). 2 of them (one on each side) seem to go into the head and disapear(no idea on how these would come out) and one other on the port side connected to a terminal(sticks out an inch or so) that has an insulating washer. This appears to be a replacable temp sensor.(by the way the tan wire broke off the connect when I was checking it. (so I will be getting a new teminal connector to re-attach). Can anyone explain the 3 wires? Are they 3 temp sensors?
Thanks in advance.

 

[emdsapmgr]

Re: '89 Evinrude 90HP question on temp sensors and alarms

Sounds like you have a number of running issues. A constant horn is an overheat. A fast beeping is a VRO problem. Both are really serious-even fatal issues if run with these alarms. You really should not let the engine run at even close to 5000 rpm's it the engine is not in the water-in gear (under load.) Good way to throw a rod through the side of the crankcase. The first warning is for fast beeps-indicates a problem with the VRO pump itself. It is an indication that the pump has no incoming oil supply. It is possible that the pump is actually ok, but the oil supply line may have air in it. You should pull the oil line off the pump, prime the oil hose bulb till oil comes out of that hose end, then reconnect it to the pump and clamp securely. The overheat could be due to a bad water pump impeller. When you were running the engine, did you have a strong water telltale coming from the cowling? Two of the tan wires go to switches in each head. Once the heads heat up to 212 degrees, the switches will go to ground, sounding the constant overheat horn. 212 degrees is hot and requires you shut the engine down till you know the reason for the overheat. These are on/off switches, not temp sensors (variable). You can disconnect the tan leads to both switches to temporarily test/disable the overheat warning system. If the engine will only run at high rpm's it is possible you may have internal carb issues.

 

[RickM101]

Re: '89 Evinrude 90HP question on temp sensors and alarms

Thanks emdsapmgr. So the 3rd tan wire goes to a sensor that goes to the temp gauge in the console? Also, just running for a minute is enough time to raise the head temp to 212 to force it into limp mode? There was good water coming out of the little hole near the cowling, if that's what you mean. And yes, the engine did not want to stay running at low rpms.

 

[emdsapmgr]

Re: '89 Evinrude 90HP question on temp sensors and alarms

That third wire would not feed a temp gauge in the dash. As I mentioned, the head switches are just a simple on/off switch. That type of signal won't feed a dash gauge that is looking for a variable signal over a specific range. It's possible the third tan wire goes to the remote-mounted oil tank. All connect to the horn in the control box. I think the SLOW system of reducing rpm's is limited to the 120/140 V4 models only and would not be installed on your engine. If the engine won't idle, possible the idle passages in the carbs are restricted. A strong telltale indicates the water pump impeller is functioning. You can still have an overheat if one of the two thermostats is stuck shut. (one thermosat controls each head.) If one sticks shut, the cooling water cannot pass out of the block and that one side of the block can quickly overheat.

 

[RickM101]

Re: '89 Evinrude 90HP question on temp sensors and alarms

Thanks again emdsapmgr. Think it might be wise for me to seek a local shop to get an idea on whats wrong. Carb re-builds and vro issues etc. Are these typically worth repairing or put the $$ towards re-powering?

 

[emdsapmgr]

Re: '89 Evinrude 90HP question on temp sensors and alarms

A starting guideline would be to take a compression test. If the powerhead makes good compression, it could be worth putting some $ into. Carb overhauls are typically not cheap, but you'll enjoy the results.

 

[RickM101]

Re: '89 Evinrude 90HP question on temp sensors and alarms

Finally got a chance to do the compression test. This is what I have:
100psi starboard top cyl
110psi starboard botton cyl
120psi port top cyl
115psi port bottom cyl

From this it does seem that it would be worth it get the work done, but I would like your opinions. Thanks!

 

[emdsapmgr]

Re: '89 Evinrude 90HP question on temp sensors and alarms

The factory recommends compression to vary 10% between cylinders. Your starboard top cyl is out of spec. It is very possible that the engine may run for another 10 years that way. Personally, I'd probably pull the starboard head off and visually inspect the top cylinder. I'd specifically check the top ring to make sure it is still whole (intact). If you don't find anything unusual, put a new head gasket on it and go boating. It should run fine with 100 lbs compression.

 

[RickM101]

Re: '89 Evinrude 90HP question on temp sensors and alarms

Thanks emdsapmgr, I will line up a good mechanic to check it out.

 

[Yargerville]

What will cause buzzer to sound when key is on , motor not running.

 

[flyingscott]

Start your own post instead of hijacking an 8 yr old thread.