84 25hp cooling and compression problems

Hello.
Its an E25TELCOS - 1985, sorry for incorrect heading. It overheated last time it was out pretty bad and stopped pumping water (not in that order). I replaced the water pump, still did not pump. Took it to an Evinrude dealer / marina to have a professional look at it, and after they replaced the water pump determined it did not pump water, and that the compression was at 75 & 45, and that the engine was on its way out. I picked it up to look at it myself.

So, being at work and not able to take a look until tomorrow, I assume that the water jacket is clogged with crap. I intend to pull the exhaust cover off to take a look to see how much mud and stuff is in there, along with pulling the cylinder head to check the gaskets.

Not being an outboard motor head, or having much experience with them, and being very worried about it, does it sound like the culprit is going to be one or both of the things I plan on checking - or does the way the compression looks tell a more sorrowful story?

Thanks for your speculation in advance,
Geoff

Re: 84 25hp cooling and compression problems

Take a close look at the pistons and cylinder walls when you pull the head and exhaust cover. If they are not scored, maybe you lucked out and just blew the head gasket.

Re: 84 25hp cooling and compression problems

Pull the head and post a pic.

Re: 84 25hp cooling and compression problems

I pulled the head and the exhaust cover - I did not find any obvious blockages. The thermostat looks like it has seen better days, and had silt around it. So - is it possible that the engine overheated due to a bad thermostat, blew the headgasket, and now the backpressure is keeping the water pump from flowing?.? (Long shot). Here are pictures of the gasket, head, and cylinders - they are not scored at all.

Re: 84 25hp cooling and compression problems

Put the head on a pane of glass and make sure it doesn't wobble. If so, figure 8 motion on a piece of 400 grit sandpaper.
Looks good to me. Try putting the lower unit in a bucket and turning the driveshaft with a drill and seeing the pump will work. If so, I would consider pulling the powerhead and checking the water tube grommet to see if it's swelled or melted and blocking the water tube.
A bad thermostat could cause overheating for sure.
JBJ

Re: 84 25hp cooling and compression problems

How hard / painful is it to pull the power head?

Re: 84 25hp cooling and compression problems

On mine (84 35hp) isjust 6 bolts holding it to the midsection.

Re: 84 25hp cooling and compression problems

Cool. The schematic is really busy, looks like I have my work cut out for me tomorrow after the rain.

Re: 84 25hp cooling and compression problems

4 bolts, 2 studs from the mid section up with SS nylock nuts I think 1/2" not easy to access but mine where not seized, the stud was nd I tap the base a little with a soft mallet.

Re: 84 25hp cooling and compression problems

Make sure you clean the water passages in the head too. From the pic, there's debris in there. For piece of mind take the water cover off of the head too. The gasket is only 3-4 bucks.
Then you know the entire system will be clear.