'85 25hp piston pics

[Trickle56]

In the middle of a head gasket job. Just wanted to get y'alls opinion on the shape of these?

 

[jbjennings]

Re: '85 25hp piston pics

They look fine to me, although it's hard to tell. I can't see the water deflectors in the water jackets, are they there or are you replacing those as well and have the old ones removed? Any reason for the head gasket job? Just curious..... The compression before and after the head gasket job might tell you as much as the appearance of the piston tops. The tops are perfectly normal; if there is no scarring on the cylinders, or piston skirts as seen beneath the intake bypass covers, I wouldn't worry about them.

 

[Trickle56]

Well I have a over heating problem i'm trying to correct. 200 degrees within 5min at idle. She's peeing ok could solid stream then not so good. Ive gone through the water pump cleared the tell tale. Got a lead on here that the head gasket could be leaking exaust gases into the water jacket puttin bubbles in the cooling system. The compression is 120 on both cylinders before the head gasket job. That is on a cold motor though. Still haven't completely put it back together to recheck compression.

I am curious to the water deflectors. Where are they located and how do I replace them?

 

[jbjennings]

Re: '85 25hp piston pics

You're in good shape on compression. It won't go up when the engine is warm, but 120 on both is good. It's normal for it to go down a little bit, actually, when warm (just MY experience with a 2-stroke outboard).
The water deflectors are in the water jackets. They are like pencils made of rubber and force the water to take the correct path around the cylinders. You should see the heads of the water deflectors flush with the heads, inside the water jackets. I beleive there are 2 of 'em.
Part #9 and #10 in this diagram, which is not necessarily for your motor but should give you an idea where yours go. There are ridges in the water jacket that will help locate them.
If you're getting a good hard indicator stream on idle, I'd suspect a bad thermostat, or bad exhaust cover gaskets, and head gasket for last resort. Usually there will be a little steam or an inconsistent stream from the indicator with a bad exhaust cover gasket, but not every time.
http://www.crowleymarine.com/johnson-evinrude/parts/44302.cfm
Good luck,
JBJ

 

[jbjennings]

Re: '85 25hp piston pics

I looked at the pics again in your post. Whoever told you to check the head gasket did good, because you have to remove it to replace the water deflectors, anyway. I just don't see the deflectors in your pic. That would definitely make it run hot, but to be honest, I don't have the experience to tell you why they're not there to start off with....... Overheat melted them????
ANyway, I hope you get it fixed. I'd replace the thermostat while you're at it since they're not high priced.
Later,
JBJ

 

[Trickle56]

Thanks jb. Actually my first instinct was to check for a bad thermostat but to may surprise it was removed from the last owner. So I ordered one a well to throw in there. Thank for the info on the exhaust gasket I least have another route to take if this thing continues to over heat. I also will be looking into gettin water deflectors. From what you described I don't remember seein any in there. Could be a possibility as well for its bad behavior. Appreciate your help and happy boating.