Multitude of Issues...In dire need of help!

[capsnumber1]

I am going to try to explain my issues with my 1989 120HP Evinrude engine as clearly as possible, local mechanic is stumped and backed up three weeks before he can even look at it.

As I stated I have a 1989 120HP Evinrude 2 stroke with VRO. When the key is turned on, the warning horn sends out a constant alarm. The engine has not even been cranked yet and this constant alarm goes off. Yes, the water pump was just replaced and the engine is peeing fine. I disconnected the alarm sensors from the t-stats and the oil tank and the alarm continues to sound.

The second issue on top of the alarm is even more confusing. The engine starts strong but idles rough, it stays started but sputters and bucks, it does the same for just off idle and low speeds.

The third issue is the strangest and most frustrating! This problem is intermittent. The engine will run fine at high speeds most of the time. However at times the engine will refuse to go above 2500 RPMs. When you try to go over 2500 RPMs the engine will buck hard, it shakes the entire boat. Last time I had it out I was running at about 4000RPMs and it suddenly started that bucking and continued until I pulled the trottle back to under 2500 at which time it went back to running normally until I tried to go over 2500 RPMs again.

I am told this could possibly be slow mode, but the engine seems too old to have such a modern feature.

Any help would be appreciated. Plugs are Champion QL16V, just replaced, and compression is good in all cylinders. The engine only has problems while under a load, it runs fine on the muffs. Alarm is the same in and out of water and never goes off.

 

[dsinger]

Re: Multitude of Issues...In dire need of help!

Well the alarm is just a trip to ground. If you say you have them all disconnected you will have to wait on someone else to help because I don t know. Have you checked the spark when the motor starts the bucking and could it be missing a cylinder when it is jerking around. I have found power packs or any pluse driven ignition part have two minds one when they are cold and one when they are hot. You might try heating your power pack with a hair dryer while out of the water and listen for any change in the motor.. You might also try a drop cylinder test while on the water when it starts to act up. Did it all just go to hell at once on over a period of time. I would be interested to know what color the plugs are.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

Don't know how these issues developed. Got the boat and motor used at a price that is worth trying to figure out the problems with the engine. I have only run the engine twice since I bought it and that is how I found these issues. I am positive it is not a cylinder problem. As for the powerpack, I have a feeling that it could be playing a large role in this crisis, but I just don't know for sure. Is the alarm connected to the powerpack? Could a faulty powerpack be responsible for the all of my problems including the alarm??

 

[Walker]

Re: Multitude of Issues...In dire need of help!

On problem one I'd bet you alarm buzzer itself is fried.
Problem 2, you probably just need a general tune-up including a good carb cleaning.
Problem 3 sure sounds like its going into SLOW mode. Are you sure its not overheating?
Slow can be triggered by 2 things. Either the heat sensors or by a bad powerpack.
An OMC manual for your motor will describe the testing procedures for the heat sensors and the powerpack.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

I forgot to mention that I bought a new alarm buzzer and it does the same as the old. I don't know what else could trigger the alarm. The alarm buzzer is not the problem.

When you say heat sensors, are those the termostats or something different?

I have a good feeling you are right about the problem number 2 solution

I also feel that problem number 3 is being caused by the thermostats or powerpack, is there a way I can find out which is the problem without replacing both??

I am pretty sure the engine is not overheating because I can touch it without it burning me. If I feel around the cylinder heads and thermostats it feels hot but I can keep my hand on it without being burned, there are also no signs of overheating such as paint flaking or discoloration.

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

You will have to buy a model specific service manual or find a wrench who has one.

My 1988 140 looper has S.L.O.W. and quickstart so I cannot think of any reason why you would not have it on a 1989.

Once the S.L.O.W. feature is triggered, the engine must cool to 162 degrees and be turned off to reset.

If the tan wires coming off the sensors are grounded anywhere along the harness, the constant signal will sound and S.L.O.W. will be activated.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

Disregard my question about testing procedures on sensors and powerpack, I see you already answered that question - get a manual!

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

There is a diode in the tan wire located between the VRO tan lead and the temp senser tan lead. You might want to check that.

I think that it is very possible that you need to take the cover off your control and check out the wiring.

Also make sure that the tan wires are as far from the spark plug wires as possible.

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

There's a Johnson factory manual at Ebay.com right now. It is listed "buy it now" so it won't last. The Johnson and Evinrude 1989 120's are the same except for the color and the cover.

Enter 4648670074 at the Ebay search window.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

I apolozige for my incompetence but what does it mean when you say look to see if the tan wires are grounded anywhere on the harness? Also I do not have a standard control box. The ignition switch and lanyard and built into the dash by the guages, and the warning horn is underneath. The only control with the throttle assembly is the tilt/trim.

How can I tell something is wrong with this diode? Thanks!!

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

I just bought the manual. Thanks for taking the time to find it!!

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

The horn gets positive 12 volts from the battery through the wiring harness. The negative ground comes from the closing of the temperature senser [tan wire] or from the VRO.

The diode basically allows current to flow in only one direction. It can be checked with an ohmmeter. You get a reading in one direction, none in the other direction when you switch the leads.

If the tan wire lost its covering at a friction point, or has burned into an adjacent ground wire, it could be sending the signal. Something is completing the circuit to your horn.

If you disconnected the three wire lead from the VRO to the wiring harness and the temp senser wires, and you still got the horn with just the key turned to run and not started, I would say you have a shorted tan wire.

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

After you solve this wiring problem, the best thing that you can do for your motor is to replace the 4 recirculation check valves that are located in the intake manifold. I would say that doing it will make considerable headway against the idle problem. Then decarb the motor and you should be in top shape.

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

Look for a lead leaving the VRO pump and going back to a half round connector. Disconnect it only to test.

They usually stuff it back behind the Tilt and Trim box, but it is there.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

I disconnected the tan wires from the temp sensors and 1 of the 2 wires coming from the oil tank. The one wire from the tank goes into a bullet connector and the other is grounded to the engine. I disconnected that bullet connector. If I am understanding you correctly, there are three more wires that come out of the VRO pump that need to be disconnected?

I

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

Thanks for all of your help, I will run these tests tomorrow and update you on results! Thanks again!

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

Disconnected VRO wiring and the alarm still continues to sound. Wiring all looks fine with no breaks in the cable. Would a defective powerpack cause the alarm to sound?? The alarm wire from the temp sensor goes into the powerpack. ???

 

[ezeke]

Re: Multitude of Issues...In dire need of help!

The tan wire leading to the powerpack is the one that controls the S.L.O.W. function. It is risky to disable it without being sure that the motor is not overheating on either bank of cylinders.

Did the alarm sound with both the 2 temp sensors and the VRO disconnected? Pull the sleeves back on the temp sensor connectors and disconnect them with the VRO disconnected. If you get no alarm, then yes, it could be a malfunction in the powerpack.

Reconnect everything else and pull the sleeve on the tan wire leading to the powerpack and disconnect that. If that gets rid of the alarm, you will be closer to a solution.

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

yes, it did - the engine was run with both wires disconnected from the port side but the wire was still connected on the starboard side - and it still went into SLOW mode. That is why I think I have a bad powerpack. Could the faulty pack be the cause of the constant alarm?

 

[capsnumber1]

Re: Multitude of Issues...In dire need of help!

The local BoatUS has a powerpack made by Sierra in stock. I am going to go pick it up now and try it out!