Something to watch out for – maybe

[oldemtr]

So, I’m working on my Evinrude 7.5, and I discovered something –
I had the lower unit off, to change the impeller , and looked at the water pickup slot, on front of the exhaust tube.
As you know, there’s a screen in the slot, which is made from a piece of metal screening, rolled into a little cylinder, and soldered together, before installing in the motor.

Well, it didn’t look right to me, and sure enough, I found that the screen was installed with the 1/4″ wide solder joint blocking most of the slot !
I was able to painstakingly rotate the little screen cylinder around, using some dental picks, so that he solder joint was at the back, and the open screen mesh faced the slot.
Maybe this is old news to you guys, but it might be an overlooked source of overheating troubles.

[fleetwin]

Well, I wouldn’t say that it is “old news” at all. Even the most experienced guys can overlook “the basics”, and your discovery is a good reminder for all of us….

[fifty20ne]

Tips and suggestions always welcome!
I would suggest back flushing any
motor that’s not pumping water correctly,
even if the inlet shows clear? mud, bugs, &
Debris can work their way up water tube etc…

Thanks,

Bob

[Mumbles]

A 10 horse Honda was given to me once because the owner couldn’t get it to pump right and it wanted to run hot even after he installed a new water pump and T-stat. The intake screen was plugged with oil and dirt so after a good cleaning the motor ran as it should. That motor got sold and it was the easiest $1000 I ever made!

[reivertom]

I would have never though it could turn like that.

[crosbyman]

…once found a grommet between the water intakes and the water inlet to the pump the part was free floating in the cavity …drove me nuts with my 45 Classic overheating

Joining AOMCI has priviledges 🙂

• This reply was modified 4 years, 2 months ago by crosbyman.

[dave-bernard]

mercury mark 20 25 & 30, there is a welch plug between the pump and pickup under the water tube that if compromised wont pump. check to see if it is rotting out.

[fleetwin]

This is an important topic for the newer OMC 4-8hp models with full gearshift. Not only can the screen get plugged, but there is a big cavity for crap to get caught in under that horrible plastic cover…My $30 81 6hp’s impeller was busted up when I pulled it apart….I worried about impeller debris getting caught upstream….I blew out the water screen with compressed air, a few chunks came up through the water pump inlet hole in the plastic cover. Fortunately, I decided to pull that cover off, only to find a pile of impeller chunks in the large cooling inlet cavity under the plastic cover. I hate pulling these covers off, it is a total pain trying to clean the 847 sealer off the sealing surfaces, and trying to seal up the gasket surfaces during reassembly is near impossible. The plastic cover tends to deform and is no longer flat.
I’m glad I was able to overcome my laziness, such a simple issue would have driven me crazy with intermittent cooling issues for sure….

[The Boat House]

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