72 evinrude 18hp, pics of head and pistons. Clean or what??

[whitejd12]

Hey everyone,

I'm waiting on the head gasket. I've attached a pic of the head. I think I've got it cleaned up pretty good.....yes??

What about the pistons and block surface? What can I use to clean them up? I can tell they've been hot, but I don't think they look too bad. My plan is to put the new head gasket on then check compression and see how she runs. Then we'll go from there.

 

[Daviet]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

Looks pretty good, make sure head is flat and torque the head bolts in proper sequence. Warm the engine up and let it cool down and recheck the torque on the head bolts.

 

[Bosunsmate]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

Yeah looks good.
I clean mine up with wd40 and a light rag. I dont go anywhere near the metal ring around the cylinder with anything other than a soft cloth as it scratches easily and thus offers an escape for compression pressure

 

[kfa4303]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

Not too shabby. You can use a soft brush and a bit of Seafoam, Deep Creep or WD40 to try to get the gunky stuff off, but it actually looks pretty good. I just changed the head gasket on my '66 20hp last year. It was a PITA getting the old headbolts out, but the rest of the job was pretty easy. She's now tight as a drum and starts up in a jiffy usually only about 1/2 pull once she's warmed up. Be sure not to apply any sealant to the gasket itself. It's impregnated with some which will melt once the motor is maintained at operating temp for a while. These may help too. Good luck. Keep us posted.

Maintaining Johnson E & FD Serie

 

[whitejd12]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

kfa......I'm happy to hear you think they look pretty good. Are you talking about cleaning the top of the pistons w/the brush and seafoam, etc or just inside the head itself. Just don't know what I should or shouldn't be putting in the cylinders, on the piston heads etc.....as far a cleaning agents go. Also, can I use wet/dry sandpaper, 400-600 grit instead of emory cloth on head? Black permatex on head bolts, right?? Thanks.

 

[boobie]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

Wrong ! Install cylinder head bolts dry and clean.

 

[kfa4303]

Re: 72 evinrude 18hp, pics of head and pistons. Clean or what??

Yes, you can lightly brush the tops of the pistons and/or the domes of the head, if there is a bunch of build up. If it's just dark in color, I wouldn't worry about it too much. Yours look good, but some look like folks were cooking BBQ on them and have visible sludge on the internals. Boobie is right about the head bolts and gasket. Everything goes back together "dry", so to speak. Just be sure to re-torque the bolts again after the first run or two. The gasket will have released it's sealant and the head will have a chance to get hot/cold and settle. Just don't tighten the bolts too much. They're hard steel, but the housing is fairly soft aluminum. As for dressing the head, I used regular sand paper myself, but I suppose emery cloth would work too. You can wipe off any dust/debris using a rag with a bit of seafoam or similar product. Don't stress it all too much. You're not building a Ferrari These old girls are pretty simple and forgiving. Just take your time, follow the diagrams and specs and you'll be fine.