Over heat alarm

[jmoore]

Hello everyone, I'm new to the forum. I have been trolling the site for a while and finally joined. I have an issue with my 89-90 Evinrude v4 120 VRO that started last summer and the local marinas couldn't diagnose. On our first trip out last spring we made it about 1/2 mile across the lake and the solid beep of the over heat alarm went off and put the boat into limp mode. I shut it off and looked all over trying to frantically diagnose. I had water from the pump pissing out. I tried to start the motor after about 3 minutes of looking and it started right up with no alarm. We idled back to the dock and trailered it. I had the motor dynode (sp?) at the local marina and everything checked out? They said the boat had good water from pump and didn't heat up when the ran it. I took it back home thinking maybe the water inlet had been partially plugged?? The next time out we were going across calm water at approx. 35mph and went approximately 2 miles with no problems. We trolled for 2 hours and everything was fine. As the wind came up we headed back across a choppy lake and only made it 1/4 mile and the alarm went off and into limp mode we went. I shut it off and waited and restarted it and idled back to dock. Back to marina and had them take it to a lake and run it only to have them say there was no problem found and it ran fine? Again we went out to the lake and had calm water and didn't have any problems until we had to leave from the wind coming up. We made it 1/2 mile in chop at 3/4 throttle before the alarm went off and limp mode again. Every time it seems it happens in chop? We can troll for hours and nothing goes wrong. I have a good stream of water, sometimes it seems like it takes a 8-10 seconds to start pissing but if that were a problem I think it would get me trolling or on calm water. One thing I did do different last year was store it in storage unit for the winter..could a mouse of chewed thru a wire from the alarm somewhere? Would a grounding wire cause the boat to sound the over heat alarm??? Could something from my VRO be causing this?? Any advice is appreciated?

[Joe Reeves]

If you have run in the past in choppy waters with no problem, I would a$$ume that the pump is not functioning properly for some reason.

If this rig is new to you, then possibly the engine is mounted slightly too high on the transom... OR... is trimmed a little too high.

(VRO Horn Warnings)
(J. Reeves)

NOTE: I retired around 1991/92. Possibly some of the later V4 engines and others may also incorporate a fuel vacuum switch that would enable a fuel restriction warning to sound as mentioned below, an unknown factor to myself.

1 - A steady constant beep = Overheating - The V/6 engines, possibly some others, have a fuel restriction warning which is also a steady constant beep.

2 - A beep every 20 or 40 seconds = oil level has dropped to 1/4 tank. (Late model engine = Every 40 seconds)

3 - A beep every other second = VRO failure, air leak in oil line, oil restriction, (anything that would result in a lack of oil being supplied to the engine).

NOTE - If the warning horn is the black plastic (overpriced) three wire type horn, the warning horn should beep once when the ignition key is turned to the ON position. If it does not, it is either faulty or someone has disconnected it (a stupid move!). At any rate, if it does not beep which indicates that the horn is non functional, find out why and do not run the engine until the problem is corrected.

[jmoore]

I've had the boat for 3 years. The first year we didn't have any issues. The second year first trip out we did. I have the power trim control gauge but I'm not for sure how it should be set. If the engine was trimmed incorrectly would it cause the motor to over heat? I normally try to set it right in the middle on the gauge?

[Joe Reeves]

Originally posted by jmoore View Post

I've had the boat for 3 years. The first year we didn't have any issues. The second year first trip out we did. I have the power trim control gauge but I'm not for sure how it should be set. If the engine was trimmed incorrectly would it cause the motor to over heat? I normally try to set it right in the middle on the gauge?

It's always possible that you are trimming too high due to a possible flaw in the trim gauge sending unit. You can check the sending unit (somewhere at the engine area) by having the engine in the full tilt position, then moving the sending unit lever slowly while observing the gauge. The needle should move smoothly and steady with no hesitation, sticking, jerking.

[jmoore]

The trim guage does not run smoothly. It seems like it sticks then jumps. While on the water I have ran it up and down trying to see where It runs the best. If i set it to high in the water could this cause a overheat issue? This may be why the marina didn't have an issue, they knew where it was supposed to be trimmed? I'll check the guage and look at where the plate above prop sits.

[Joe Reeves]

Originally posted by jmoore View Post

The trim guage does not run smoothly. It seems like it sticks then jumps. While on the water I have ran it up and down trying to see where It runs the best. If i set it to high in the water could this cause a overheat issue? This may be why the marina didn't have an issue, they knew where it was supposed to be trimmed? I'll check the guage and look at where the plate above prop sits.

Strike what I said about sitting the gauge... I was thinking about something else. a test procedure on another post, sorry. I deleted that statement.

The gauge needle should be at the half way mark when the actual trim of the engine is halfway of course. Sorry for the error.

I do believe that due to the faulty sensor which results in a sticking gauge needle... It probably was okay the first year you had it but became flawed in the sitting period prior to the second years use. The marina of course would be most experienced and actually have no use for the gauge, hence the no overheating result.

Your relying on the flawed gauge setting would explain the overheating due to the (most likely) tilting the engine too high which in turn would cause the water pump to draw air.

[jmoore]

I was just going back thru replies and Joe you mention if the horn does not sound one time when the key is turned on it is not working correctly? My horn does not? I traced wires to the back corner of the boat this past weekend and didn't find any wires with insulation missing. I do know that the trim gauge moves erratically while driving the boat? I will run it out to the lake as soon as it warms up some and keep it down all the way and trim it by sight and by how the boat planes out and not the gauge and see what happens? Just to be safe I'm going to run it in and have the impeller replaced also. Anyone know how difficult it is to replace a water impeller on your own? Thanks for help Joe