A couple things....any info???

[toonfish]

I bought a used boat. It has a 1995 40hp johnson outboard.

It worked fine for a trip out, but know I have a couple issues.

When accelerating and going forward...as soon as I get to a certain speed the motor starts to trim up??? It will work fine sometimes, but then it will do it again. Any ideas on what this could be or what would cause the motor to trim up? and where to start when checking for culprit?

2nd thing is it is a oil injection system. I noticed that the alarm near the throttle has been disconnected. When I plugged it back in the alarm constantly goes off....even when motor is not running. I just want to make sure the oil injection is working and it is not going off because of a pump or oil injection issue. any idea on how I check this? and figure out if the alarm was just disabled because it is faulty.

The motor runs and starts great, I just dont want to blow it up, because of no oil....It is nerve racking and I may have it changed out, so I can just mix gas for peace of mind.

I would appreciate any help on this, I want to keep fishing this fall! Thanks

[Ufatz]

Take the boat to a decent marine mechanic and get it fixed. Do it NOW and you'll still get in some fall fishing. Won't take long to repair.

[toonfish]

I wish I could have figured that out for myself.....great idea! I guess I am just looking for any other advice before I do that. Obviously I can take it to a mechanic! Hoping somebody might have some experience, before I run out and pay a 1 hr. min to look at it. Sorry, just looking for a little help....before I go do the obvious.

[Retro Active]

I'm no expert or mechanic, but I did stay at a Holiday Inn last night. I have a couple of thoughts that might help..

1. You say at a certain speed the motor trims up. Is it a certain speed, or a certain throttle position? Does it do this regardless of trim position when you start accelerating? I think most motors have trim limit switch. I'm don't fully understand how it works, but I know on an old motor I had I could only trim it up so far when I was at full throttle. I don't know if this problem might be related to the operation of that limit switch. Seems to be the opposite of what you are indicating.

Otherwise maybe there's a short in a wire in the throttle lever (or somewhere else in the boat) and as the lever moves forward the exposed wire or bad switch makes contact and the motor trims up. I wonder if you could disconnect one of the two trim control positions (I assume you have one at the throttle and one at the motor) and see if it makes any difference. If not, try the other one.

2. One way to get a good indication that the oil system is working is to check your spark plugs. After normal use it's fairly common and expected to see some oil on the threads. Another is to mark the spot on the oil reservoir (if you have one) and watch after use to see if the oil level goes down. I wouldn't be surprised if the alarm you're hearing is a low-oil alarm versus a non-functioning oil pump. I don't know if that motor is advanced enough to detect if the oil pump isn't working. It almost certainly won't tell you if it's working in a degraded state. I think only the newer computer-controlled outboards could tell you that.

Just some ideas to start with...

[toonfish]

Thanks for the input. I am going to take apart the throttle assembly and start with the wires. I did call a couple mechanics today. Their thoughts were very different on the tilting up issue. One thought it has to be electrical, because even if the tilt pump was going bad...the motor should not come up as the thrust of the prop should push it against the boat. Another thought it is probably bad seals in the tilt motor,and that the water pressure of moving forward was pushing the motor up, but recommed I try adding some fluid first. ????? So we will try a couple things, frustrating.

On the Oil injection issue and removing or disabling the system, so I can mix gas instead. One mechanic told me they will not do it, as it is a liability issue??? and the other said all I have to do is plug the oil line and start mixing gas.

[Retro Active]

You can disable the oil injection, but are you sure you want to? Mixing gas is a pain in the butt, if you don't have to do it. If the alarm goes off and the motor isn't running, I would think it would have to be a faulty oil level sensor. How many times have you run it since you had it? I just can't see that alarm being anything other than an oil level alarm.

My advice would be to purchase a new sensor and see if that fixes it. A manual from the library for your motor might easily indicate how to test and replace that sensor. I can't imagine it's expensive. I don't want to ever mix gas again for my boat if I don't have to.

Regarding the trim, does the trim motor function when you experience the problem or does the motor end up trimmed up without the motor engaging? I would think it would be easy to disable the trim motor once on the water and see what happens when you accelerate. That will tell you whether the motor is causing the problem or if it's bad seals. If you disable/de-power the trim motor and it trims up, bad seals. Otherwise if the trim motor is causing the trim condition, look for that short or bad trim switch.

[toonfish]

Thanks for your help again....I am going to try what you said to test the trim. It is weird that it only does it sometimes. I have had the boat out 4 times since I got it. I'm thinking if it is a short or wiring issue, I would be able to hear it come on....we will see. I am also going to try and figure out how to disable it so I can test. If anyone knows how to do this, advice would be great.

With the Oil injection, I guess I don't need or want to remove VRO. But I do enjoy peace of mind that it is always getting enough oil. I am going to try disconnecting the overheat sensor wire and see if that is it.

[boatfixer]

Your tilt problem is more than likely in the control handle as suggested. Bad seals, no seals etc, no way at all will drag overcome prop thrust under power, no way no how.

The other thing that will give you a steady alarm is the overheard alarm. If it sounds as soon as you turn the key, regardless of temp, its possible the thermo-switch is bad. Locate the switch in the head, near the thermostat housing. It will have a tan wire coming from it. Follow the tan wire to the connector, disconnect it to see if the alarm goes away.

[toonfish]

Boatfixer......That's what I thought, I wouldn't think the water pressure of moving forward could overcome the prop thrust. Like I said I will start with the control handle and wiring. Awesome....Thanks for input.....i am also going to track that tan wire.....it is the wire at the back and port side of the motor that goes into a dime size hole in a black box right? If that is it, I should just leave that disconnected?

[boatfixer]

That sounds like the sensor.

No the water pressure won't overcome thrust. If you remember a lot of the old outboards with no power trim, when you put them in fwd gear, it actually released a lock and allowed the motor to raise if you to hit a submerged object. With older mercs, that was the way you tilted them. Point is, the thrust will keep it done.

[delcecchi]

If the water pressure overcame the thrust, the boat would stop. It is the thrust at the prop that makes it go. The water pressure on the boat limits how fast.

[toonfish]

I took apart the throttle handle and assembly.

I re-plugged the alarm and no horn went off. Then I started moving the throttle around and the alarm touched the metal on the inside of the boat and it started to go off. Does this alarm have to be grounded to work or do I have some weird short going on?

I then started to inspect the trim wires and did not notice any obvious wear but maybe a couple pinch points that could be avoided, but still no obvious wear. I looked at the wiring inside of the motor too. The wires were laying in the bottom of the motor were it is a little oily. Some points were taped and not very well at that and you could see some copper, but still dont know that this would cause the trim issue I am having.

I guess I will try to route wires a little different and tape some areas and see if that works.

As for the alarm issue, I guess I need to know if it supposed to be grounded to the side of the boat in order to work, before I do anything. Or if the two issues are related and I have some sort of weird short that may be activating the trim also????

[pinkfloyd4ever]

I've been following this thread, your situation is quite the riddle and I have nothing to help you out. I wouldn't think that the alarm needs to be grounded to the boat, therefore the alarm must need to be grounded to the boat

[boatfixer]

No it does not need to be grounded, sorta. Completing the circuit to ground is what sounds the alarm. Every "load" on a dc circuit must have a positive and a negative to work. How this system works, is by having the pos feeding the load constantly and neg open until a thermo switch or oil level switch, etc, completes the circuit by providing the negative or ground.

[toonfish]

Ok, so it is doing what it is supposed to do, I just need to find a different spot to mount it. Rather than having it touching metal on side of the boat, otherwise that will complete the ground/circuit and it will constantly be going off.

[marine_man]

Isn't your warning horn currently mounted in the control box or the tiller handle? I'm trying to understand how it's contacting the side of the boat.. and for that matter, why touching the side of the boat completes the ground - your boat hull should not be grounded.

marine_man

[delcecchi]

Are you sure the hull isn't connected to neg. on battery, if only through the motor being bolted to the hull?