What happened to this head?

[epresutti]

Folks,<br /><br />J140TXCn (J140 1982)<br /><br />I pulled the heads and I found this (see picture), it looks like the inside of the head is pitted pretty bad, this is only on one cyl. The other cyl. on the same side is very black (starboard). The inside of the port heads look fine. Also found that the head gaskets said they fit 115-135, this is a 140, did they use the same gasket?<br /><br />Cyl. Walls are smooth and pistons heavily carbed but other wise fine.<br /><br />What would cause this kind of damage to the head, do I need to replace these, if so, what else should I bee looking at/for.<br /><br />

<br /><br />Any help greatly appreciated.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.

 

[Walker]

Re: What happened to this head?

Has this motor been rebuilt. For sure a piece or pieces of ring or needle bearings did that damage. If there is no damage to cylinder wall then I'd say your motor has been rebuilt. Walker

 

[epresutti]

Re: What happened to this head?

Walker,<br /><br />Guy I bought it from (marine mechanic now out of business), said he replaced the head gaskets, he didn't say anything about re-build.<br /><br />Any additional help appreciated, do I need to replace this head? If I don't what is the long term effect?<br /><br />Thanks again.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.

 

[trollhole]

Re: What happened to this head?

My two cents would be that there is no long term effect other than a performance issue. If the piston and walls are in good shape then you should be okay. Sounds like a rebuild took care of them. The head is probably okay since it doesn't look like any metal was lost which would cause lower compression but that it was just displaced. Only effect I could see would be in the interuption of a smooth mixture of air and gas which could cause some performance issues. If it were mine I would be to do nothing.<br /><br />I'm no professional on this though.

 

[Joe Reeves]

Re: What happened to this head?

Ed..... With no intentions of stepping on anyones toes, replace that cylinder head. The OMC part number for the starboard head is 326503. Sorry to say, I don't have one left in stock.<br /><br />The resoning to have it replaced is that the engine has blown that piston in the past, and minute particles of steel etc are imbedded in the aluminum, which is impossible to remove.<br /><br />Those particles (at least one of them) will eventually (when the engine's running) glow red hot such as a model airplanes glow plug would do. This will result in pre-ignition and will absolutely destroy the associated piston.

 

[Dhadley]

Re: What happened to this head?

Double ditto, Joe.

 

[BillP]

Re: What happened to this head?

That pitting may not be from fragments of metal in the cylinder. It could be from carbon build up causing hot spots...that is what a burned piston looks like. How do I know? I had a 1980 Johnson 140 that looked like that on the lower left cylinder. When I got all the carbon buildup off the piston crown it had those pitts. One of them burned all the way through the piston crown and resulted in 40 psi compression.

 

[denniz]

Re: What happened to this head?

If you run that head it will cause hot spots and trash that cyl.sorry d

 

[Neil]

Re: What happened to this head?

I regognise this.<br /><br />I had a similar problem (see post sept 3rd heelp.. and previous in June)<br /><br />My Evinrude 140 developed a serious missfire one day. Removed the head to find cyl had shed a pin and parts of it were imbedded in the head. After removal the head was identical to yours, maybe not quite so bad, but similar.<br /><br />I have had engine rebuilt and remored on one cyl. Johnsom mechanic advised head would be OK as long as all possible contaminants were removed.<br /><br />I do still have a problem and post is ongoing for those interested.<br /><br />NG

 

[ODDD1]

Re: What happened to this head?

Judging by the punch marks in the head, looks like a ring had previously broken up in that cylinder...looks like all the ring has been dug out, and the worst of the surface damage ground off.....this head has been running, and will continue to do so....why invest in a new head on a 20 year old motor???

 

[aeronutt29]

Re: What happened to this head?

This looks just like the top of my Merc cylinder after ingesting a broken reed valve. I concur with the opinion that the piston has been replaced at some time in the past. If you plan to run the engine hard, replace the head. On my merc, the only way to fix the problem is to replace the whole block since it doesn't have a removeable head. Since you are lucky enough to have the option, take it. Since I don't have the option of replacing the head, I run extra oil and won't ever ask the motor to make more than about 70 percent of max power. I hope that this will prevent those hot-spots from getting out of hand and causing another catastrophic failure. If you don't mind backing off the throttle, you might get away with not replacing the head.

 

[epresutti]

Re: What happened to this head?

Folks,<br /><br />Thanks for all the replies, my intention is to rebuild and restore this mortor to as close to original factory condition as I can. I will be spending the winter (actually starting now), completely disassembling this motor, I don't think I will split the case, seeing as it looks like these are new pistons.<br /><br />I had a cooling problem, so I want to completely clean the water jackets, check water tube, rebuild carbs, etc.<br /><br />Given what everyone has said, I think I will replace this head.<br /><br />Does anyone have an idea of what is a reasonable price for the head, I also want to replace the head bolts, and actually all bolts, screws and nuts that are rusted.<br /><br />Thanks for all the help, I will probably be taking more pictures as I go through this process. I am not a mechanic, I have mechanical ability and got the OEM shop manual in addition to my clymer, really like the shop manual.<br /><br />Thanks again.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.

 

[DJ]

Re: What happened to this head?

Ed,<br /><br />Ditto, Joe and Dhadley.<br /><br />You've got time on your side. Keep a close eye on e-bay for the head(s).<br /><br />Also might want to check: www.twincityoutboard.com

 

[Hooty]

Re: What happened to this head?

I'd go ahead and remove the crankcase,ball hone the cylinders and replace the rings, rod bolts and lower seal as long as I was in there.<br /><br />c/6<br /><br />Hooty

 

[epresutti]

Re: What happened to this head?

Hooty,<br /><br />If I hone the cylinders, do I need to replace the rings with a different size?<br /><br />Thanks in advance.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.

 

[ob]

Re: What happened to this head?

Agree with JOE and DEHADLEY , that head is toast.At very best if all steel particulates are removed the numerous pits alone will become a haven for carbon deposits that will not disperse .

 

[Hooty]

Re: What happened to this head?

No sir you'll use the same size rings as pistons. If pistons are std., use std. rings. The top of the pistons will have the "size" stamped on them. It'll be std.=standard, .020=.020" oversize, etc. Check each piston in case one has been over-bored more then the others.<br />I just read another post and it reminded me; you should take lots of pictures (digital, polaroid, whatever) and label wires and everything. Put bolts, nuts, parts, etc, in baggies and label them.<br /><br />g/luck & c/6<br /><br />Hooty

 

[maked]

Re: What happened to this head?

hey Ed <br /> here is a quick thought, of course every one is great at spending someone elses money , this may save you some. If you are going to take that advise and redo rings, pistons etc, have a look in your phone directory or on the web for a local ring MANUFACTURER, these wonderful people produce what you want and the joy of having rings custom built could save you about 80% of the cost of originals. At least that has been my experience at this end of the world, ($23 instead of $116). Also any helpful machine shop can clean up pistons, regrooving or filling, for much less than the cost of older hard to get (solid gold?) originals. Good luck and have fun

 

[epresutti]

Re: What happened to this head?

Guys,<br /><br />Thanks much, Hooty, I think I read the same post, I have been taking pictures as I remove each part, cleaned a set of steel shelves which is now my "Motor Parts" Museum display Have permanent markers and those freezer bags with the white area you can write on.<br /><br />Thanks again folks, I'll let you know how it goes.<br /><br />I will be posting this chronical on my WEB site with the boat rebuild that goes along with it.<br /><br />Thanks again. Any other comments are certainly welcom.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.