1988 60HP Mercury - Water Spray @ Upper Exhaust

AMD Rules · #1 May 23rd, 2005, 08:40 PM

Motor is new to me, and I am getting discouraged trying to figure out why it is spitting a lot water out of the upper exhaust ports just beneath the cowling.

New impeller has been installed. Pee stream is ok, but somewhat weaker than I expected. Blowing out the telltale tube indicates no blockages.

I removed the lower unit again (4th time in 2 weeks) to take a peek at the water line & its seals. When I took it apart the entire mid-section, water tube, exhaust tube, etc was covered in a grey, oily milkshake. Looks like frothy water & oil to me. The engine has been run on muffs, and in a barrel but never on a lake since I purchased it.

The water pump housing does have the tube seal, nylon washer, and soft rubber guide tube. The water tube does fit into a seal up at the top exhaust plate, but the tube can be removed or rotated easily by hand.

The exhaust tube seems to fit ok up into the exhaust plate, but can be pulled off quite easily. I'm assuming this is normal.

I took extra precuations to re-assemble the lower unit to mid-section and made sure the water tube went together properly.

Still I have this motor spitting at me out the upper exhaust, and a thick milky oily residue coating all of the internals of the entire mid-section and internals of lower unit after it has been run.

Should I just run this as-is, knowing that the engine is not overheating and it does have a pee stream and a new impeller? I feel like I am missing something obvious.

Moody Blue · #2 May 24th, 2005, 02:24 PM

I have always been under the impression (right or wrong ?)that it is normal for water to be expelled from those exhaust ports. All that water that is pumped in must go somewhere and my assumption is that it is expelled with the exhaust gas. The telltale is only a small take-off from the water jackets to show that the water pump is operating. The exhaust tube is held onto the exhaust plate by a loose friction fit. It is normal to be able to pull it down. Do you have a rubber seal for the bottom of the exhaust tube at the lower unit ?

As for the oily residue coating the inside of the midsection I'm not sure. Would think that should be relatively dry. If the water tube can be easily removed by hand you might be getting some leakage from the exhaust plate seal but where is the oil coming from ? How is the oil in the lower unit ? Is it possible that oil is leaking past a seal from the lower unit into the midsection ?

AMD Rules · #3 May 24th, 2005, 04:48 PM

Thanks for your thoughts regarding the exhaust tube Rod. I almost emailed you specifically to ask, knowing that you just went through the process of installing one...lol I do have the rubber seal at the bottom.

Oil in lower unit is AOK. Just changed, complete with new pump impeller.

I guess I'll have to run it like this for a while, and check the mid-section in a few weeks time to see if th eoily residue it there again. I cleaned it out well before I put it back together.

Maybe I just flooded the engine really bad (new carbs & bad adjustments for a while c/w no start and a few hours of swearing) and that mixed with my somewhat leaky upper water pipe spray to make a milkshake.

Motor runs, and seems to be cool.

Cross my fingers and go for it I suppose. Unfortunatley thats a big lake out there and I don't enjoy paddling upwind.

AMD Rules · #4 May 24th, 2005, 04:50 PM

Anyone have a cross-sectional view of the water path through a 3 cylinder outboard so I can better understand what might be going on? Manuals don't seem to describe the cooling water route in much detail.

Silvertip · #5 May 24th, 2005, 05:35 PM

At speed, water and exhaust exit the engine through the center of the prop. Sitting still, the water (in the lake) causes back pressure so exhaust relief ports are provided which are the ports just below the cowl. It is perfectly normal for water and exhaust to exit there.

AMD Rules · #6 May 24th, 2005, 05:52 PM

It was running on muffs though and spitting a lot. I just dont want to go up in smoke :-)

Based on all opinions I've heard....I should be aok to run it as-is, but probably have a leaky seal up top somewhere, contributing to more than average spray.

AMD Rules · #7 May 26th, 2005, 04:55 PM

Here's few pics with the power head off.

First on is looking down the mid-section:

Then showing the consistency of the milkshake, on my finger:

Then looking up under the powerhead, beneath the exhaust plate:

Surely this mixture can't be normal is it?

Moody Blue · #8 May 26th, 2005, 07:53 PM

Man that can't be right. What a mess. Sure looks like the oil/water combo but from where ? How do the plugs look after it been run awhile ? Must be exhaust gases mixed with water that is accumulating when the motor is at idle. When at speed, the exhaust gases are drawn directly down the exhaust tube. At idle the exhaust gases exit into the midsection and out the relief ports. Is this after or before you cleaned it ?

Nos4r2 · #9 May 27th, 2005, 12:00 AM

Have you checked out the condition of the gasket between the exhaust plate and the powerhead? Maybe it's leaking between the water system and the exhaust there.

AMD Rules · #10 May 27th, 2005, 04:32 AM

The exhaust plate has been removed, and shows some interesting characteristics:

Lower spark plug does not look abnormal. No water visible.

Notice that the water cavities in the exhaust plate are clean.

The exhaust port is slightly wet/oily, and the cavity beneath the lower end cap is coated with the oily mixture.

Gasket is intact, but does have some moist areas in the center section between the water cavity and the crankshaft cavity.

Rod, these images are after I had cleaned it out, and then run the engine on muffs for 10 minutes or so. Its been recommended that I check the lower crank seals, and that will be my next area to look at.

Thanks again for all advice.

AMD Rules · #11 May 27th, 2005, 07:15 PM

Any advice how to get that lower end cap off, without having to dismantle the whole crank case? I don't see any tapped puller holes, and it won't budge as it is. Must be a secret....anyone know?

wjhall273 · #12 August 25th, 2008, 09:06 PM

HELP !!!, My 1980 50hp 4cyl is only providing exhaust out of the prop. The motor runs very rough and then chokes out and will not restart. After a while it will restart and exhaust normally at an idle but with any throttle increase it starts blowing incredible exhaust even in neutral.

I suspect the exhaust tube seal but don't want to start removing parts without guidance.

Thanks for any replies...

Chris1956 · #13 August 26th, 2008, 11:06 AM

AMD, Normally both end caps may be removed without splitting the crankcase. You need to loosen the bolts on the crankcase near the endcap, remove the end cap bolts and it may be pried out easily. There is a shim on the upper endcap, and rubber orings on both. You might replace the orings and reuse the shim.

emckelvy · #14 August 26th, 2008, 02:59 PM

I'm thinking that if it's really really hard to pull, you could tap those (3) holes and either use a harmonic balancer puller or (very very carefully) use a slide hammer, just a few 'knocks' on one hole then move to the next one, etc. That way the pull will be 'evened out' and you won't get the carrier 'cocked' in the hole.

Once the carrier is out, be sure to note the direction and position of the crankshaft seals before you remove them. Lips should face downwards when pressing-in new seals. Lube the lips of the seals and the bearing carrier O-ring with waterproof grease prior to installation.

BTW, when removing the carrier, resist the temptation to pry on the "tangs" where it bolts down. It's very easy to break them. If you're going to pry, do it between the main body of the carrier and the block. Just be sure you don't mar the surface of either when prying.

HTH & G'luck.......ed