Mercury 1989 25hp that has sat a LONG time

Hello All,

This is my first post.

I have an 8' addictor boat with a 1989 Mercury 25hp engine with quicksilver side controls. The last time I had the boat in the water was 1994.. long story. Anyhow, I want to get it up and running again and have a few questions. Since it sat for a long time and was not pickled or prepared for this long time, what do I need to look at and replace before I attempt to run it? I bought an impeller assy but I am sure I should replace some seals as well. I have an old paper repair book but would also like to find an online source for the repair manual with color pics. Also the wire harness that has a plug to the quicksilver control is missing. I am unsure what model control I have, but will look into that later this week.

Any advice or online resources on bringing a long sitting motor back to life. Also being a 1989 its essentially only 5 yrs old as it sat since 1994 and still looks pristine under the cover. Lower drive below water line has some peeling corroded paint since it did spend some time in brackish water before I owned it.

Best regards,

Marc

pull plugs and clean or replace, Squirt some marvel mystery oil in cylinders,rotate engine by hand to make sure everything is moving properly.clean and flush fuel tank,lines,primer bulb,pump filter,etc. Carbs. might need overhauling,removing,thoroughly cleaning and rebuilding with a new kit. Drain lower unit oil and refill it. Install fresh fuel in your clean tank.

Hello All,

I am resurrecting this old post. I ended up not getting the boat running last time I asked this, but am working on it again. Since I am crazy busy I may also be interested in a good place to take the boat in to have the work done to get it going again. Can anyone recommend a good shop in the Los Angeles area. I am in Glendale CA.

Any idea on rough cost to have the lower unit serviced, new impeller and cleaning of carbs to get this going?

Best regards,

Marc

All the recommendations above ignored changing the impeller BEFORE firing it up.

Jeff

Good luck on finding a shop to work on it. You definately need to have the engine fogged before the first fire off. You want to lube the bearings and seals as a precaution. You would be better off finding a small ma and pa shop I doubt a large shop would even take it in to work on due to its age.

And changing the impeller! After sitting that long it's hard to imagine vanes not breaking off to plug up something.

Jeff

Absolutely replace the waterpump, rebuilding the carb and fogging the cylinders are the must do items for your motor. The carb has the primer and fuel pump built into it and both of those diaphragms are gonna be brittle by now.

Hello All,

I have been working on the boat and today I decided to drain the lower unit oil and when I did nothing drained out. So I then I decided I should pull the prop shaft. Before I started I realized that all around the lower skeg was coated in dusty oil. Best guess is the main seals dried out and due to heat and pressure the oil seeped out. I pulled the prop and shaft and found that there must have been a bit of standing water in the lower unit and there was a bit of rust on one quadrant of the large gears that were likely exposed to water. What rust there was there was very soft and pretty much just wiped off. and the gears still look good. So my question is what do I do now. I have a repair manual, but part of me wants to just bring it to a shop and let them sort all this out. Anyone have a ma/pa type shop in the Los Angeles area they recommend?

I have attached a few pics and you can see on the metal where the seal failed where its all black.

Open to any advice and suggestions

Both the drive and prop shafts have an area where they run in needle bearings, bearings that run directly on the shafts. If there is pitting in this area the shaft(s) are scrap.

Jeff

I would clean up the gears etc (I use diesel fuel - it's a good degreaser and displaces any residual moisture) - get everything as shiny as you can and then put it back together.

From there you can pressure test the unit with a small compressor. Pump 15 psi into the unit (through the oil fill hole) and see if the pressure holds.

If it doesn't you can submerge the unit in a tub of water and look for leaks.

At minimum I would tend to replace the o-ring on the bearing carrier and the pair of seals (propshaft seals) on the prop side of the bearing carrier, but if you have more issues it may be better to test it first and then get everything you need to do all the issues at one time. At least it will come apart easy enough.

The only real booger to do is the driveshaft seal. It can be a bit tedious to remove and re-install the pinion gear, plus it has to be torqued to exact spec or you can damage the gears. There is a special socket that goes on the splines of the driveshaft to do this but it's pricey for a "one time" operation. Otherwise, you can swap out everything else with some basic tools.

galamb said:

I would clean up the gears etc (I use diesel fuel - it's a good degreaser and displaces any residual moisture) - get everything as shiny as you can and then put it back together.

From there you can pressure test the unit with a small compressor. Pump 15 psi into the unit (through the oil fill hole) and see if the pressure holds.

If it doesn't you can submerge the unit in a tub of water and look for leaks.

At minimum I would tend to replace the o-ring on the bearing carrier and the pair of seals (propshaft seals) on the prop side of the bearing carrier, but if you have more issues it may be better to test it first and then get everything you need to do all the issues at one time. At least it will come apart easy enough.

The only real booger to do is the driveshaft seal. It can be a bit tedious to remove and re-install the pinion gear, plus it has to be torqued to exact spec or you can damage the gears. There is a special socket that goes on the splines of the driveshaft to do this but it's pricey for a "one time" operation. Otherwise, you can swap out everything else with some basic tools.

Click to expand...

Thanks for the reply,

I forgot to mention that I found no shavings at all on the oil plug magnet. Also the propshaft assembly feels smooth when I rotate it in my hand. Im thinking just that main o-ring failed from sitting. I need to remove the forward gear, but the main driveshaft is in the way. When I remove the lower and place it in a vice, does the driveshaft just slide out or do I need a special tool. Also once the driveshaft is out, how do I remove the forward gear. Does it also just slide out or does it require a tool? My repair book is horrible and leaves so many steps out. The Youtube videos have been a great help but i have not found one on servicing the lower gears on a 20/25 hp Merc of my year range.

I plan to order anything that says seal in advance from this assembly to have it in advance and will likely tear it apart once things arrive. Any other often damaged Items I should buy?

As for pressurizing it to 15psi, is there a fitting for this, or do I just use a rubber tipped nozzle and hold it and then have someone watch the regulator Gauge?

Thanks in advance.

Marc

You should be able to worry out the forward gear without removing the pinion. It will be (meshed) with the pinion which is keeping it in place at the moment (with the propshaft removed). You can just get it to clear the pinion if you push the top of the gear towards the (nose) of the unit and get the bottom of the gear to kinda pivot your way. There is a bushing, bearing and a race (cup) "behind" that gear, but with a bit of fiddling they will come past (under) the pinion.

If you want to take out the driveshaft then you need to undo the pinion gear. There is a nut at the very bottom of the pinion. You can get a closed box wrench on the nut but there just isn't enough room to undo it (although the new ratchet style closed wrenches might work but it would be a pain). This is why you need the Merc socket that fits on the splines at the top of the driveshaft - use it to "undo" and re-torque the pinion if you take it off - so if you can avoid removing the pinion that's always the easy way out.

To pressure test the lower unit you can use anything that will allow you to keep the air hose either attached or tight. I rigged up a fitting. I picked up one of those gear oil pumps from a discount auto place (the little pump that goes on the gear oil jug with a couple of fittings for the different sizes you find on lower unit) - I just took the one that fit my lower units and fit it into a piece of hose with a schrader valve on it. Then I use my tire inflater that has the gauge attached. Anyhow, you should get the idea - anything that will let you observe if it's holding pressure or not.