Small leaks between lower unit and upper unit

Hank Bass

Cadet
Joined
Mar 20, 2011
Messages
20
Hi,

I have an Evinrude/Johnson 100hp 4 cylinder 1983 model that I have a question on:

When I pulled it out yesterday to run the motor using muffs, I noticed about 3 pinhole sized water leaks on the left side where the lower unit meets the upper unit. There were I believe another 2 on the right side. They would squirt water either at idle or at 3000 - 4000 RPMs.

Is this a problem or can I continue to run it that way? If it's serious, what kind of effort will there be to fix it? I also saw what appeared to be an "intentional" hole at the front of the upper unit that also squirted although it looks like that hole should be there. Other place it was shooting water out of was the fin holes but I think that are also intakes? Don't know for sure, could be muffler exhausts?

Any help on the pinholes really appreciated. My primare use is saltwater fishing.

Hank
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Small leaks between lower unit and upper unit

First off, you shouldn't be running the mtr at 3000-4000 rpms on muffs unless you want some internal part to come out and say "Hello". As long as the mtr isn't overheating this is perfectly normal.
 

Jim311

Petty Officer 2nd Class
Joined
May 31, 2011
Messages
169
Re: Small leaks between lower unit and upper unit

Stupid question but.... Why can't he run it at whatever RPMS he wants as long as it's on water?

As far as the water "leak" are you sure you don't have too much pressure running from the hose to the motor? It doesn't require but like 15 PSI, but the average house has like 50 pounds of water pressure. Too much pressure will cause the water to come out of other areas, and isn't a good idea.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Small leaks between lower unit and upper unit

Reread above ... like the motor might blow up! The joint between the LU and midsection is not sealed. Dumping WAG's here is not helpful.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Small leaks between lower unit and upper unit

Jim311, he said he was running on "MUFFS". Not in the water.
 

Hank Bass

Cadet
Joined
Mar 20, 2011
Messages
20
Re: Small leaks between lower unit and upper unit

Judging from all the return posts, I may have too much pressure on the muffs and shouldn't be running the rpms so high. I guess the consensus if I keep using the motor in the water (letting the pump suck in the water) it should be ok?

Please let me know, I'd hate to blow the motor as it's a commercial grade motor and runs good.

Thanks to all.

Hank

Hi,

I have an Evinrude/Johnson 100hp 4 cylinder 1983 model that I have a question on:

When I pulled it out yesterday to run the motor using muffs, I noticed about 3 pinhole sized water leaks on the left side where the lower unit meets the upper unit. There were I believe another 2 on the right side. They would squirt water either at idle or at 3000 - 4000 RPMs.

Is this a problem or can I continue to run it that way? If it's serious, what kind of effort will there be to fix it? I also saw what appeared to be an "intentional" hole at the front of the upper unit that also squirted although it looks like that hole should be there. Other place it was shooting water out of was the fin holes but I think that are also intakes? Don't know for sure, could be muffler exhausts?

Any help on the pinholes really appreciated. My primare use is saltwater fishing.

Hank
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: Small leaks between lower unit and upper unit

If you are the type of person that it bothers, drop the lower unit and clean the mating sections, or you can just run it and not worry about it.
 

yoster

Petty Officer 2nd Class
Joined
Aug 19, 2010
Messages
117
Re: Small leaks between lower unit and upper unit

Just to be clear, the engine shouldn't be revved like that even IN water, in neutral. The engine needs to be in gear when revving up that high. A neutral no-load rev that high isn't good.
 

Hank Bass

Cadet
Joined
Mar 20, 2011
Messages
20
Re: Small leaks between lower unit and upper unit

Thanks to all for the help. I'd rate this forum as tops of any website. Everytime I've had a problem, all the posters have hit the problem right on the head. Thanks again.
 

archcycle

Chief Petty Officer
Joined
Sep 21, 2009
Messages
647
Re: Small leaks between lower unit and upper unit

I don't know if you've pulled the gearcase off before, but if you do, you'll see it's all open in there. No gasket between the lower unit and the midsection. Free flowing water.
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Small leaks between lower unit and upper unit

Never/ever run the motor past idle on muffs. Muffs are only making sure the motor runs.
High Revs on Muffs is BAD.
 
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