honning cylinders

realtree280

Petty Officer 3rd Class
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Oct 5, 2005
Messages
76
is it ok just to hone the cylinder walls and replace pistons and rings on a 1980 johnson 15 horse j15rcsd , was thinking of just deglazing the cylinders what do you exsperts think ?
 

OBJ

Supreme Mariner
Joined
Dec 27, 2002
Messages
10,161
Re: honning cylinders

Should be no problem realtree if the honing will not put the bore size over specs after honing. You got about .004 to play with from standard bore size.
 

realtree280

Petty Officer 3rd Class
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Oct 5, 2005
Messages
76
Re: honning cylinders

thank you i was told i have to bore the cylinders from a small engine mechanic , i am not saying i dont have to but i was sure there is a chance i can just hone
 

realtree280

Petty Officer 3rd Class
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Oct 5, 2005
Messages
76
Re: honning cylinders

right now 83 per cylinder i decided to replace pistons since a half - - - mechanic put a sleeve in a stripped out spark plug hole and something damaged top of piston
 

realtree280

Petty Officer 3rd Class
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Oct 5, 2005
Messages
76
Re: honning cylinders

i have priced everything online and for about 350 dollars i can get pistons,rings,wrist pins,complete gasket set,complete seal kit,carb kit,coil, power packbearings,and a new head on ebay any thing else you can think of ?
 

Paul Moir

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Nov 5, 2002
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6,847
Re: honning cylinders

Bearings often don't need to be replaced. Since it's a 2-stroke, all the bearings are roller/ball bearings and really last a long, long time unless something nasty happens to them. Keep the con rod ones as a set though, like keep all the top cylinder wrist pin bearings together. Pull it apart and inspect the bearings - if they're blued, pitted, corroded, flattened etc, then replace them. It seems to me the bottom main is usually bad.<br />Replacing the seals is wise.<br /><br />Helicoiling a spark plug hole is common practice, and if it's done fine there's no sense in replacing it. Often we have short thread plugs in these aluminium heads, so it's a frequent problem. The helicoil is stronger than the original threads and personally I see it as an improvement.<br /><br />But if it's a complete botch job, I see your point.<br /><br />Don't forget the various specialized sealants & goops you'll need. Do not use RTV for anything anywhere on an outboard. If it's a salt water engine you'll need a few bolts to replace the ones you will certainly break. I don't see thermostat and water pump (minimum impeller) on your list, but that's not really part of the powerhead rebuild. Unless overheating is what wrecked it. <br /><br />EDIT: Saw your other post. Forget about that last bit. ;)
 

OBJ

Supreme Mariner
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Dec 27, 2002
Messages
10,161
Re: honning cylinders

The way the plug fits into the head is a headache when a helix coil needs installed. You can't get the regular tap in all the way to complete thread for the helix coil. Fact is, you need three taps..one to start the tap, one to get it in a little deeper and a finish tap to complete the helix coil thread. This means modifing two helix coil taps for this type of installation. An un-knowing mechanic might not know this and force a helix coil tap in and mess up the head which could cause problems. <br /><br />I guess what I'm asking is, are the cylinders scored or messed up or is it just the head that is damaged from a botched up tap job as Paul said.<br /><br />It would also be a good idea to mike the cylinders and see how much wear there is. You may be suffering from just sticky rings which a good de-carb might cure.
 

zuup_2000

Seaman
Joined
Feb 8, 2004
Messages
50
Re: honning cylinders

If you are thinking about honing them yourself, the drill mounted hones dont remove much material, and are pretty easy to use for deglazing a cylinder wall. <br />Please be aware that any drill is much too fast for a hone, and you will have better luck if you get an adjustable speed controller for your drill, rather than trying to sqeeze the trigger a certain amount. You want to get a good, properly angled cross hatch to make sure your rings seat properly. <br /><br />Also, prior to using a drill mounted hone, get yourself some muratic acid to clean the cylinder walls of any aluminum deposits that might be left on from the old pistons. Just wipe some acid on the walls (be careful not to let let it contact any aluminum mating surfaces) with large Q-tips and look for any bubbling. <br /> There are also different grit hones for different types of rings(steel, moly), so be sure to get the one you need. <br /><br /> Its very easy to do, but you will want someone there to help you. I use a mix of 50/50 kerosene and motor oil in a spray bottle to lube it while I hone, and I have someone there to spray while I hone. You can watch the pattern of the oil in the cylinder to be sure your crosshatch is at a good angle.<br /> If your just going to have a shop hone it, I guess Im typing for nothing, but I figired Id mention it. Im sure others have different ways to do it, but Ive done alot of auto engines, outboards, and 2 strokes this way. Ive never had a problem.<br /><br /> That little motor should be a piece if cake, but after doing a V8, you will need some tylenol.
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: honning cylinders

If you do the honing yourself, cut out a sheet metal disc the diameter of the cylinder, a lid from a tin can will work, and drop it to the bottom of the cylinder. This will keep the hone from snagging the web where the connecting rod come's through. If this happen's it will break the stone. Plus, you can hone evenly full length of the bore. Don't use a ball hone, a Sunnen hone with wipers would be best.
 

realtree280

Petty Officer 3rd Class
Joined
Oct 5, 2005
Messages
76
Re: honning cylinders

the guy who fixed it actually put the sleeve for spark plug in crooked thats why i am replacing head,but thanks for all the info this has been a great exsperience so far on here , by the way anyone on here willing to loan a manual for this motor to me , as always i take great care of everything, well probly asking for to much but anyway. my last question is do i need to chamfer the exhaust ports after honing ?
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: honning cylinders

Yes, chamfer the ports, but do it very lightly,just breaking the sharp edge is enough.
 
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