1994 40hp trim falls

[loganmenk]

Hey guys, I have a new outboard on my 1969 Thompson 14ft.

Motor: 1994 40hp 4cyl 2-stroke
S.N. 0G098660

The problem is the power trim doesn't hold. I can trim up and down, but the motor falls as soon as I let off the switch.

I read the stickies. I have checked the oil and it was full. There is oil around the shaft on the cylinder. I am guessing there lies my problem. I guess my real question would be is this my problem and how hard is it to replace or fix?

Thanks,
Logan

 

[jerryjerry05]

Re: 1994 40hp trim falls

Sounds like the o-rings in the pump/motor might be bad?
You have the manual?
The factory manual is the ONLY way to go.
Sent U a PM.
Location?
Motor looks REALLY clean!!

 

[loganmenk]

Re: 1994 40hp trim falls

I read the manual linked in the stickies. I will order one of your's though just to save time and so I have it without internet.

Anyway, I suspect that there is a bad o-ring somewhere. How hard is it to change these?

The motor is super clean! Only about 12 hours on the hour meter. The guy I bought it from had it on a pontoon but moved 1500 miles away. When he came back the boat had rotted away and he sold me the motor for $400!

 

[RRitt]

Re: 1994 40hp trim falls

oil leaking out of shaft is A problem but not THE problem. If oil gets out then water gets in. That system will split like a pipe during hard freeze if it gets too much water inside. THE problem is either a rusty spring in the spool valve, a bad poppet in the spool valve, a crack in the nylon manual release seals, or a bad poppet in the check valve. My advice would be to get a full rebuild. There are too many possibilities and the full rebuild just fixes them all. If you fix things one by one until it works it can land anywhere from $80 to $280 in parts plus 4-16 hours of time. A full rebuild only takes the time to pull, pack, and ship. It costs about $250 and isolates you from parts & time unknowns. Check ebay listings.

If you want to try & save money then split ram from pump. There are two socket head bolts in base of ram. After removing them gently rock and pull apart. Do not pry on the sealing face between ram and pump. You will see a spool sticking out from manifold. The spool is going to be rusted in place. Just leave it alone. Use a magnet to pull out the needle from middle of spool. Underneath the needle there is a spring. If the spring is rusted enough to be weak then that is your problem and a new spool valve kit will fix it (you still need to fix that oil leak though). If the spring is not rusting away then it probably isn't anything easy to find and you'll end up spending a lot more time & $$ trying to figure it out.

 

[loganmenk]

Re: 1994 40hp trim falls

I see some kits are around $100 and some around $50. One guy rebuilds them for $219 with parts.

What all comes in the kit? Has anyone done this that can give some first hand experience? I see the system as a basic ram and hyd. pump. Is it much more complicated than this?

I also have searched and found many people state that the problem may be in the manual release o ring.. Is this a common thing? I didn't see any sign of water in the oil when I filed the unit.

 

[Moody Blue]

Re: 1994 40hp trim falls

I had the same motor a number of years ago and it had the same leakdown problem.

Turned out to be a broken manual relief valve. The tip of the plastic valve had broken off. I found one on ebay for about $40 and replaced it in about an hour. Problem solved.

Not saying this is your problem but may be worth a look.

 

[loganmenk]

Re: 1994 40hp trim falls

I read about that problem earlier. Does the valve come out if unscrewed all the way? Then I have to go in to retrieve the broken piece?

How did you like the motor? I haven't had the boat out yet with the new motor..

 

[Moody Blue]

Re: 1994 40hp trim falls

There is a metal retaining ring/clip that has to be removed in order to remove the relief valve if I remember correctly. The broken tip was easily plucked out of the cavity with a pair of tweezers.

The motor was awesome. Smooth, strong and reliable. It was the first "large" motor I owned and couldn't have been happier with it. I had mine on a 14ft boston whaler type hull. Only issue I had (common) was a bad oil level float that kept sending a false low-oil warning beep.

 

[RRitt]

Re: 1994 40hp trim falls

I see some kits are around $100 and some around $50. One guy rebuilds them for $219 with parts.

What all comes in the kit? Has anyone done this that can give some first hand experience? I see the system as a basic ram and hyd. pump. Is it much more complicated than this?

I also have searched and found many people state that the problem may be in the manual release o ring.. Is this a common thing? I didn't see any sign of water in the oil when I filed the unit.

im the guy who rebuilds them. there are three or four kits. one for the spool, another for the poppets, another for the pump gearcase & release valve, and the nylon release valve itself. There is some overlap between kits but i do not think I have ever seen a single kit that fixes all. So you would typically do well to know the problem before buying kits.

there is a stainless steel "C" clip on the nylon release valve. If you take the clip off then the valve will screw out through a whole in side of transom clamp. It doesn't sound like the valve from your description. when the release valve tip breaks off the enigine usually goes up but won't come back down. So pull out the release valve and inspect before running out to buy another. when tightening the release valve don't torque it against bottom. It is not that kind of seal. i usually back out 1/8th turn from bottom.

 

[Moody Blue]

Re: 1994 40hp trim falls

It doesn't sound like the valve from your description. when the release valve tip breaks off the enigine usually goes up but won't come back down. So pull out the release valve and inspect before running out to buy another. when tightening the release valve don't torque it against bottom. It is not that kind of seal. i usually back out 1/8th turn from bottom.

In my case the motor dropped from full-up to full-down in a period of about 2-3 hours, and the cause was the broken relief valve.

Good point about not over tightening the valve. Not knowing, I always reefed on the thing not wanting it to leak. Little did I know until I took out the pieces, how it actually worked. The valve just has to be lightly seated.

 

[loganmenk]

Re: 1994 40hp trim falls

Well, it looks like I found the problem! I checked the valve and this is what I found..

Is the tip broke off of this? I guess I don't know what a good one looks like.
I put the o-ring on strait and it seems to work great now....

 

[RRitt]

Re: 1994 40hp trim falls

you have to get the tip of that stem out of the manifold without damaging the manifold. It will be tightly wedged into the very bottom of that hole. you can usually see it with a very small pointer-type light. Best way to get it out is to take the system completely apart. Secure the manifold (aka base) and then drill a tiny little hole right into the middle of the plastic tip. then use a screw extractor to pull it out. take care not to damage the aluminum. after the tip is out you can just buy a new release from mercury for $35-$40 and re-assemble.

 

[loganmenk]

Re: 1994 40hp trim falls

It looks like only a small bit broke off. The groove for the o ring is still there and the lip catches it fine.

I suppose just using it the way it is is not recomended? The trim operates fine and has held over 24 hours. What causes these to break anyway?

 

[Moody Blue]

Re: 1994 40hp trim falls

If I remember, the tip is a conical shape. That is the part that broke off and is lodged inside the valve body. You really need to get it out. Try carefully poking in there with a fine tipped hooked scribe and see if you might be able to catch it and pull it out. Be carefull you don't damage the seal seats by gouging them.

Over tightening causes it to break. When snugged up, the conical seat bottoms out in the valve body. By continuing to tighten the valve you end up twisting it and the small tip breaks off. Its a common mistake. We overtighten them so that they don't leak, but in doing so we break the valve.

 

[loganmenk]

Re: 1994 40hp trim falls

Thanks guys! Looks like I will be fishing for a plastic piece!

I need help identifying this hose coming from the lower unit.. What am I looking at and where does it go?

 

[Moody Blue]

Re: 1994 40hp trim falls

That is a connection for a speedometer. It would connect to the tubing from the dash speedometer. Basically it takes the place of the traditional pitot tube that is mounted on the transom. If you look closely at the leading edge of the lower unit you will notice a small notch. That notch is the pickup point for that tube you have.

 

[loganmenk]

Re: 1994 40hp trim falls

Thanks! That explains why I didn't notice it on the other boat when I looked at the motor.

The plan was to have her splashed by the end of the weekend, but it looks like the weather will be cruddy. Wind, cold, and rain.. This is why I live in Arizona right??