Mercury Classic 40 hp

[lawdog]

I have a couple issues with my approximate 1991 Mercury 40 horsepower. The starter doesn't always engage, I turn the key a couple times and then it goes, kind of random how many times, but once it engages it works fine.

Also on the power tilt, it goes a little way and then makes a squeal and stops. I can move it by small increments with many starts, squeals and stops along the way. I'm wondering if this maybe is a fluid issue? I've never done anything with it and never had problems before now.

I'm wondering if these are known problems and have easy fixes? Boat doesn't get a ton of use, but I want to keep it in good working order. THANKS.

[jac714]

I can't help with the starter but the tilt sounds like fluid, get your transom perpendicular to the ground raise the motor all the way up and engage the tilt holder (on the left (port) side of the transom bracket) and then check the fluid level.

I had the same problem this spring.

[lawdog]

Thanks I will try that. What does it use for fluid? Where do I check it?

[CAMAN]

The trim uses Automatic Transmission Fluid, raise the motor as high as it goes, and you should see a plug of some sort on the side of the motor bracket or coming off the pump. Remove it carefully and top it off. Reinstall plug before lowering motor back down. Unfortunately it may not fix your issue, my Classic 50 does the same thing after I came down on a rock, I think it blew a seal, and I haven't wanted to dig into it just yet.

The starter is an easy fix, find the starter motor and look for the shaft coming out of it with a gear and spring installed on it. That shaft and gear are dirty, clean it as good as you can with some WD40 and wipe off as much as you can leaving a VERY light film to lubricate it. You don't want much because it will just collect dirt and jam up again.

[jac714]

Many of the Mercury's of that era have a single ram hydraulic system if yours is like that there should be an electric motor between the motor brackets on your transom near the bottom of that there is a fill port, use Mercury tilt and trim fluid (Basically ATF with some extra stuff added) to fill it to the bottom of the hole.

Another thing to check is the manual relief valve, it is located on the right side of the hydraulic system (mine is a white plastic screw) take this out adn see if it has a round tip and 3 o-rings if eiter of these is not true you need to replace the manual relief.

Good Luck

[lawdog]

Thanks for the great info guys! I knew there'd be some good advice here.

[boatfixer]

Hope and pray that its just a fluid level issue. Mighty pricey unit replacement unit. No individual parts available for that one.

[lawdog]

Hope and pray that its just a fluid level issue. Mighty pricey unit replacement unit. No individual parts available for that one.

I haven't had a chance to check yet and need to find the fluid for it, but HOW PRICEY if it isn't???

[jac714]

I was told that the hydraulic system for my motor (similar era Merc 75hp) that it would be around a grand to fix if it was not the manual relief or the fluid.

[CAMAN]

I haven't had a chance to check yet and need to find the fluid for it, but HOW PRICEY if it isn't???

I did some research when mine started acting up, and the cheapest one I could find was used and about $400. The new ones were about $500-600. Then add shop-time in and it will easily double the price.

[Surface Tension]

You said it makes a squeal and stops.

What stops? Is the trim motor running while it stops or is the trim motor stopping?

If it is the trim motor first thing is clean your battery connections and make sure your battery is charged.

That could also be the problem with the starter.

If that doesn't clear it up then take the engine cover off and trace the motor wires(2)to there connections and unplug them.

Pull them though and direct connect to a battery, polarity doesn't matter as the trim motor will run the trim up or down according to their orientation. If you still have the motor stopping I'd suspect worn and or dirty brushes in the trim motor or a water leak into the trim motor.

Time to remove the trim motor and pump.

First off if you backed out the relief valve you'll need to turn it back in.

Outboard trimmed up and on its leg.

You should have the wires pulled through the lower cowling.

Next you'll remove two pins, one is on top the ram and the other is on the lower left side bracket.

To do that you have to remove a smaller knurled pin in each location.

Look close on the upper end of the ram and you'll see a small pin going through the center. Knock that out with a narrow punch.

The larger pin will slide out now.

The lower left pin has the same small knurled pin, you'll knock that out entering through the bottom bracket.

Now remove the larger pin.

The trim and pump should come out now. Note you'll have to lift the outboard up to do that.

At this point you can bring your trim motor and pump to an auto electric shop or to a marine dealer.

I'd opt to the auto electric shop as that is what they specialize in. Not that a marine dealer can't handle it but at this point you don't want a new motor, you want yours fixed.

Or you can fix it yourself.

On top the motor are 7 screws. Remove a screw from each corner leaving the bleed screw and 2 screws that hold the wiring.

The end frame will now come out and the end frame is where the brushes are.

Check for water or oil in the motor, you don't want either.

Are the brushes warn enough so that they aren't making good contact or are they dirty and hung up?

If so clean or replace the brushes. Pull the armature out, careful of the stem on the end that goes into the pump. Inspect and clean. Look for burnt areas where you brushes ride and clean.

After I reassemble the motor I fill and test before installing.

It is much easier that way. If you filling a trim when installed you have to park on a hill and lower the tongue on account the trim is not plumb when mounted. Remove the bleed screw on the top of the end frame when filling. Trim up and down, recheck fluid when the trim is in the up position and set it on its leg. When your all done replace the bleed screw and its o-ring.

[lawdog]

The tilt seems to be much better with the fluid topped off. Not making much progress with the starter though. Its a brand new fully charged battery too...

[boatfixer]

Does it spin just fine? just wont go up the bendix and engage?

[lawdog]

No it doesn't spin or anything, just a click, or maybe it turns a 1/2 turn or something 4-5 times in a row then the next time it works just fine and goes up and engages and everything.

[CAMAN]

No it doesn't spin or anything, just a click, or maybe it turns a 1/2 turn or something 4-5 times in a row then the next time it works just fine and goes up and engages and everything.

That sounds like the brushes or bearings are shot

[marine_man]

Yep.. I agree.. sounds like it's time for a rebuild.

marine_man