Warning siren on Evinrude that won't go away

[Boatnsteve]

Hello there fellow boaters! I have a problem that I'm hoping someone can offer some advice on. I have a 1995 Evinrude 90HP (model E90TLEOR) that I bought a few weeks ago. I had the impeller replaced before I put it in the water and it ran flawlessly for about 4 or 5 hours of pretty much flat out use. On the way back from a couple mile trip I heard the warning siren sound. I found that from a cold start it would take about 30 seconds for the siren to come on. No other signs of problems.

Since I have absolutely no record of prior maintenance (I got it from a guy who recently bought it used and never used it himself) I decided to haul it in to the local marina where the mechanic replaced both thermostats. He ran it, at idle, for an hour and got no siren. I started it up and after throttling up for a very short time I got the siren again. Argh! As before, engine sounded and performed fine. I decided to call it's bluff and took it out for a couple of hours. Performance was excellent and the siren cut in and out occasionally, but was usually on.

This is an oil injected setup and the oil consumption appears to be fine (oil reservoir empties out at about the same time as the 20 gallon fuel tank), so I'm sure it's getting adequate oil. I'm using name brand 2 cycle oil.

The obvious question is... do I have a bad sensor, or is there something else I should be looking at?

Thanks!

Steve

 

[hidef]

Re: Warning siren on Evinrude that won't go away

The easiest way to diagnose a bad sensor is to start unplugging them until you find the culprit. You have a sensor in the oil tank for low oil a sensor in the VRO2 pump for no oil and two temp sensors. If you unplug all four sensors and the alarm still sounds you have a bad wire in the wiring harness whish is grounding out the system causing the horn to sound or a bad horn.

 

[emdsapmgr]

Re: Warning siren on Evinrude that won't go away

Your system should be setup to indicate just which sensor is triggering your problem. If the horn is constant, you have an overheat. If the VRO pump is failing, you will get a horn 1/2 second on, 1/2 second off. If the oil tank is low, you will get a horn 1/2 second every 20 seconds. I have seen horns which go bad. Also, you may find a defective horn will give an incorrect signal. For instance, my horn goes constant when the oil tank is getting low.... If the horn is bad (quirky,) follow hidef's procedure.

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

Thanks for the responses! I will give the siren troubleshooting a shot this weekend. I'm going to speak with my mechanic tomorrow and see if he did anything regarding the water deflectors (another forum suggested this to someone else). I don't think I have a head gasket problem as I'm getting plenty of power and I would assume that wouldn't be the case if the gasket was blown enough to cause such easy overheating.

How can I measure oil consumption? Obviously if the engine isn't getting enough oil that would cause overheating. As far as I can tell, only having run about 2x 20 gallon tanks through the boat, oil consumption seems to be roughly one full reservoir for one 20 gallon tank of gas.

A long shot... how about brand/type of 2 cycle oil? The previous owner filled up the reservoir and it was during that period that I didn't have overheating. It's only been since I started putting in my own oil (Valvoline) that the siren has gone off. Coincidence, most likely, but figured I should mention it.

Thanks,

Steve

 

[hidef]

Re: Warning siren on Evinrude that won't go away

Changing from one brand of TC-W3 to another won't cause an alarm.

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

Interesting results this weekend. I started the engine up, but after the first sputter (takes a bit to get it started) I noticed the overheat siren was wailing away already! We drove around for a bit and it never ceased. Next day, after 18 hours of sitting there, I turned the key and before engaging the starter it started wailing again. Obviously the engine couldn't be overheating, so it is possible all I have to deal with is some bad sensors. Of course it could be that I've also got an overheating problem.

I've ordered two head gaskets and intend on pulling the heads off and replacing the water deflector tubing as I suspect it's in need of replacement anyway. Do I have to replace the sensors at the same time or can the be replaced with the heads on?

Steve

 

[emdsapmgr]

Re: Warning siren on Evinrude that won't go away

I wouldn't run that engine a minute with that horn going off till you determine if it's overheating or not. You can rent a laser temp gun at most any local auto parts store. Fire up the engine in the lake. Check the cylinder head temps at both idle and a planing speeds. If you find the engine is heating up to normal 143-155 degrees, then look to troubleshoot the other aspects of the electrical system and visually check the powerhead internals behind the heads.

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

Yup, that would be the prudent thing to do. But for sure I know one or both of the sensors is bad. That's a definite. I've also felt the heads after a fairly long and vigorous trip and they didn't feel excessively hot. At the moment I would say if there is an overheating problem it is minor. My mechanic, when he replaced the thermostats, said the water deflectors looked fine. However, he didn't replace them and so that's what I'm going to do myself.

Steve

 

[Borgey401]

Re: Warning siren on Evinrude that won't go away

I personally think it's crazy to run that motor with the siren going off like that. You're pretty much looking for disaster if you ask me. If it sounds like it's just the sensor but why even risk it? It makes no sense to me to risk blowing up the motor when this could all be avoided. I wouldn't call any overheating problem "minor" either. Just my $.02

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

It's what I would call "risk management". The question is, how likely is it that there's a real overheating problem? The two common reasons for overheating (bad water pump impeller and/or thermostats) have been eliminated. My mechanic also said the deflectors looked OK (I do wish he had just replaced them). Compression is good, the heads don't feel excessively hot even after significant usage, and I ran it close to full throttle for more than an hour before I realized the alarm was going off because I couldn't hear it. Yet the only indication that there is an overheating problem is the sensor. Which, as I now know, is giving out a false overheating single.

There is such a thing as a "minor overheating" problem. It's the opposite of a catastrophic overheating problem. The type that will seize up an engine in no time flat. I know I don't have anything that serious because my engine would be a bunch of molten metal right now if there was something seriously wrong. Not to say that a "minor" problem can't eventually cause major damage, because it can. But in the risk assessment equation this sort of thing matters because if I thought there was even a small chance of a major problem I'd have this thing on it's trailer in no time flat.

Therefore, while it is possible there is some overheating, it's more probable that there's nothing wrong with it. Weighed against pulling it out of the water on the off chance something is wrong is the certainty that boat wouldn't be used at all due to various circumstances. Given how important it is to us (we are on an island) risking an unlikely catastrophe against a definite "catastrophe" to our enjoyment of it... it wasn't too hard to decide what to do. If we get burned, we get burned. But so far we've had about 10 hours of practical and pleasurable use that would not have been possible if we had just assumed the worst. According to our method of accounting. Life is too short and our summers here are even shorter

Steve

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

PS... I forgot to add that the replacement cost for this particular engine matters. Our other boat has a 50HP Honda four stroke on it. Under identical circumstances as described above I'd not be running it now. I can afford to go out and get another 16 year old two stroke if the calculated risk goes sour, I can not afford to go out and replace a 9 year old four stroke.

Steve

 

[emdsapmgr]

Re: Warning siren on Evinrude that won't go away

You can get a severe overheat, even with a new impeller and new stats. It is possible the powerhead has sand or other debris inside the head cooling passages-under the head covers. This restriction can cause poor water flow through the heads. This can esp. be a problem for those engines used in salt water, or for fishermen who may fish/troll in shallow sandy areas. I'm not saying this is the overheat problem on your engine-only that there are other ways for that block to overheat than can be attributed to new impeller, stats, and diverters. I think the concern is that running any engine with even a "slight" overheat winds up reducing the long term durability of the powerhead. Since you've done your risk assessment, why not just cut the wire to the horn?

 

[Boatnsteve]

Re: Warning siren on Evinrude that won't go away

I'd rather have the sensors working as they should because at some point it will probably save my bacon Actually, one thing I have to do is properly mount the horn so I can hear it when at full revs.

My plan is to pull the heads, inspect for damage/debris, replace the diverters, and do the sensor work at the same time. After this week the boat will be pulled for the season anyway so I can work on it out of the water and not worry if I run into complications. My mechanic should be back in action sometime late September so if there's more work to be done I can have it done over the next 8 months before the next season starts. Tach is also wildly wrong and I'd like to get that fixed too.

Any advice on how to replace the sensors? I have zero experience with that sort of thing.

Thanks!

Steve