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1969 Merc 110 - Watet Pump?

H

Howard A

Member
First off, I'm a newbie in the world of outbards. I recently accquired the above motor. It starts and runs and water comes out of the water pump weephole(?) at a steady stream..... for a few minutes and then stops. Am I looking at a new water pump, or might there be something else going on? The outside of the intake screen at the foot of the engine is clean. Thanks for any guidance.
 
First off, always turn the engine off when it's not pumping water. Are you using the muffs and a garden hose or is it submerged in water? Sometimes the hose and muffs don't work well, if it's in the water and stops pumping through the weephole you need to drop the lower unit and inspect the pump assembly
 
Damien77 said:
First off, always turn the engine off when it's not pumping water. Are you using the muffs and a garden hose or is it submerged in water? Sometimes the hose and muffs don't work well, if it's in the water and stops pumping through the weephole you need to drop the lower unit and inspect the pump assembly
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Imnning it in a barrel with water. So you're saying open her up?
This will be my first surgery...

R
 
No worries; I have replaced the water pump on the lower unit of a Merc I/O and it is quite simple and on that unit, I had to put the throttle lever in forward to get it to separate from the main body - don't know if that is necessary for outboards - maybe the experts can chime in. I think there are water pump kits available. Having the service manual is priceless; the manual guided me through rebuilding my outboard carbs and diagnosing a no-spark issue.
 
If you don't know when the water pump was replaced its always a good idea to replace it anyway but try something. Put the engine back in the barrel, make sure the water level is significantly up the mid section to the bottom of the swivel pin or so. Start the engine, let it warm up and just put it in forward gear and let it idle and see if it keeps pumping water. I have seen where the exhaust bubbles coming up from the propeller hub are drawn into the intake above it and cause a loss of water pump pressure while in neutral. Putting in forward gear moves the exhaust away from the intake screen and she'll pump water fine.
 
fitz73222 said:
If you don't know when the water pump was replaced its always a good idea to replace it anyway but try something. Put the engine back in the barrel, make sure the water level is significantly up the mid section to the bottom of the swivel pin or so. Start the engine, let it warm up and just put it in forward gear and let it idle and see if it keeps pumping water. I have seen where the exhaust bubbles coming up from the propeller hub are drawn into the intake above it and cause a loss of water pump pressure while in neutral. Putting in forward gear moves the exhaust away from the intake screen and she'll pump water fine.
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Thanks for the idea on running it in gear. Unfortunately, I had the same results. Once the manual arrives, I'll be ordering parts.
 
Does the engine actually start to get hot? You should be able to keep your fingers on the cylinder cover or exhaust plate without discomfort. These engines run rather cold to the touch. It's strange that the engine pumps fine and then stops. So when you change the impeller if it is in pieces make sure you get all six blade pieces out or they'll wind up upstairs in the block passages and cause overheating. Also become familiar with the process of shimming the pump housing correctly if you replace the base gasket since it can an effect on the roller bearing preload and pinion gear height.
 
"Also become familiar with the process of shimming the pump housing correctly"
Will that be in the manual? If not, where might I get that information
 
"Does the engine actually start to get hot? You should be able to keep your fingers on the cylinder cover or exhaust plate without discomfort."
I haven't checked that, but the portion of the lower unit housing that's above the water is pretty hot. Is that from exhaust gases?
 
It should be in the manual and this is only if you replace the water pump housing and gasket. If just an impeller change or the stainless liner then don't worry about shimming the housing.
 
Got the repair manual today. Ready to start the water pump repair shortly, but first, two things:
1. Is there an alternative to the Mercury Marine Perfect Seal sealing compound referenced in the manual or should I use that specifically?
2. Any words of advice or things to look out for before I begin?
 
At long last, I'm back on this project. I'm having a hell of a time getting the impeller on. Either the impeller key moves on the shaft and/or the impeller does not want to slide down over the key.
 
"Glue" the key to the shaft with heavy grease. (Some people use super glue.)

Jeff

PS: Getting that LU back up there requires a few tricks. Let me know when you are ready and I'll help you out.
 
I have done this many times with no issues.----But for a novice it is best to use some " string " to pre-bend the vanes so the impeller slides down on the key.----String made from ladies lingere or underwear works the best.----Putting the lower unit back on is also quite easy.----Just make sure the o-ring is in place below the spline.-----Water tube guide in place on the pump outlet.---Shift lever confirmed in forward and lower unit in forward and it slides together.
 
I showed the 8 year old granson how to install an impeller on HIS outboard ,10 hp Johnson.-----He did most of the wrenching.-----I would say it is not that hard to do an impeller.
 
The impeller is in. I wound up using a small nylon tyrap to compress and bend the
Impeller vanes. Used vaseline to "hold" the key on the shaft. Waiting on some more parts before completing the assembly. Thanks guys for the guidance and advice. I'll let you know if I have any issues installing the lower unit.
 
Mercury Marine Perfect Seal is a great multi-purpose sealing compound that can be used on gaskets, propshafts (to prevent corrosion) bolts etc. It remains flexible and doesn't shrink I have used it for years - they probably suggested using it on the driveshaft where the impeller sits.
 
Quicksilver said:
Mercury Marine Perfect Seal is a great multi-purpose sealing compound that can be used on gaskets, propshafts (to prevent corrosion) bolts etc. It remains flexible and doesn't shrink I have used it for years - they probably suggested using it on the driveshaft where the impeller sits.
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I didn't see a recommendation for Perfect Seal on the ware pump shaft, but it's recommended for almost everything else.
 
Trying to get her put together. The pull rope was dry rotted and the Mercury factory replacement rope I purchased is much larger in diameter and hangs up when recoiling. I'm thinking I should just buy some smaller diameter rope. What type of rope should I look for?
 
I think it is ----" double braided " ----Or something like that.------Very low stretch.-------Any small engine shop should have it on a spool.
 
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