1972 Evinrude yachtwin 4hp overheats

[creekster]

engine starts and runs good but overheats. Had impeller replaced but still overheats. Was told it's possibly an o-ring at top of narrow cooling water tube. Much labor $$ to fix. Does this sound like correct diagnosis?

 

[R.Johnson]

Re: 1972 Evinrude yachtwin 4hp overheats

Replace the entire pump assembly, not just the impellor.

 

[Paul Moir]

Re: 1972 Evinrude yachtwin 4hp overheats

There is no o-ring at the top of the cooling tube. It joins into the adapter plate with a compression fitting. So no, I have to disagree with his diagnosis.<br />Does mist come out of the idle exhaust ports when you run it in water? <br />These engines are easy to work on yourself. Would you consider doing the repair yourself? If there is a clog it will be labour intensive, but the parts are pretty cheap.

 

[highaltitude]

Re: 1972 Evinrude yachtwin 4hp overheats

on an engine this small i would check the cylinder for scoring. i know it sounds a little off, but a scored cylinder on an engine of this size will cause heat. a thorough way to check will be through the exhaust.+

 

[creekster]

Re: 1972 Evinrude yachtwin 4hp overheats

Thanks for the input on my 4hp overheating Yachtwin. I'm looking for an engine manual and will attempt this surgery myself (heck, I could fix a VW bug pretty good 30 years ago!)

 

[Paul Moir]

Re: 1972 Evinrude yachtwin 4hp overheats

Creekster, have a look at this post:<br /> Click here. <br /><br />The 3hp is an ancestor of your yachtwin, and the same holds true for it. Take the l/u off and blow up the water tube to see if it's totally clogged. You'll need to remove the powerhead if it's clogged, and I strongly suggest purchasing an impact screwdriver before attempting that. This inexpensive tool is indespensible for removing the slotted hold-down screws. It will quickly become your favorite!<br /><br />EDIT: Oh, and another peice of advice: put a clamp on the pull start to hold it all together before removeing the big bolt in the middle if you plan to take it off. It's one of those trying things that you need 4 hands to reassemble. If you don't have to mess with it, clamp it up and forget about it.