1999 115 hp Johnson Hole In One Piston

[Ric & Jul]

We have a 1999 115 hp Johnson. It has a hole in one piston with no other noticable problems. Is is best to repair it or replace the motor? Also how do we find out what caused this and how to keep it from repeating in the futur. The motor is on a 25ft pontoon boat with oil injection. How expensive a fix is this. This is our first boat. We don't have a lot of knowledge on this. Thanks for you help.<br /><br />Ric & Jul

 

[DJ]

Re: 1999 115 hp Johnson Hole In One Piston

Ric & Jul,<br /><br />I would think that engine is very much repairable.<br /><br />As a ROUGH estimate, you can figure a minimum of $200.00 per cylinder.<br /><br />More than likely, if it is a carbureted engine, one of several things happened.<br /><br />1. A clogged carburetor jet leaned out one cylinder.<br /><br />2. One cylinder overheated due to faulty thermostat or water pump.<br /><br />My bets would be on #1.

 

[Capt Ken]

Re: 1999 115 hp Johnson Hole In One Piston

Djohns, that price doesn't include labor does it? Ric&Jul, you can figure to get that engine rebuilt, and that's what it would take is a total rebuild, will cost between $1600 to $2200 depending on the shop. If a shop tells you they can just replace that one cylinder, run don't walk out of there. The engine has to be completely torn down to remove that one piston and not to renew the other three is plain crazy. Included in the rebuild is rebuilding the carbs (which caused the problen) and new water pump.

 

[DJ]

Re: 1999 115 hp Johnson Hole In One Piston

Capt. Ken,<br /><br />No, I was referring to them making the repairs themselves.<br /><br />Your prices sound spot on for a "professioanl" rebuild. <br /><br />Thanks for the clarification.

 

[lorax]

Re: 1999 115 hp Johnson Hole In One Piston

Capt. Ken<br />Why do you say it would be crazy to just service the one cylinder? When you say renew do you mean hone and rings? What about bearings?<br /><br />I'm asking because I have an old inline that scorched the No. 3 cylinder. The motor has good (140psi) compression on the other 5. I don't know whether I should fix it or part it out.

 

[Trent]

Re: 1999 115 hp Johnson Hole In One Piston

I think what Ken was trying to say is that since you have the engine torn down. Go ahead and spend just a little more and do it right and do it all. Hone and re-ring and new bearings or bore if needed.

 

[DJ]

Re: 1999 115 hp Johnson Hole In One Piston

Lorax,<br /><br />Agree with Trent. Ric & Jul are talking about a 2-3 year old engine. Might as well, "renew" it.<br /><br />You surely can put just "one" in, if you want to.<br /><br />2-strokes are a little different. Usually when a piston melts down, all the debris goes out the exhaust-not in the oil pan-like a four stroke. Usually, the bearings are OK, I do reserve the right to qualify, that last statement.<br /><br />If your in-line 6 (I assume Merc./Mariner) has a bad cyl., I would expect a carb. prob. feeding that cyl.

 

[sho305]

Re: 1999 115 hp Johnson Hole In One Piston

They are known to be very reliable. If you have 140, that is good compression and if you can fix what caused the problem, I would have no problem doing one cylinder on that. If it has lots of hours('99-probably enough), do bearings and rings on the rest. The problem with a set of 4 pistons, is it gets expensive. It makes sense to replace anything in there that needs it, and rings/bearings are cheap. 100 compression and you have big problems.

 

[Hooty]

Re: 1999 115 hp Johnson Hole In One Piston

Ric & Jul,<br />Personally, I wouldn't have any problem at all with reboring one cylinder (if necessary) replacing one piston, honing all cylinders, re-ringing and rebuilding carburetors. I doubt seriously if you've worn any other parts out.<br /><br />c/6<br /><br />Hooty

 

[Dhadley]

Re: 1999 115 hp Johnson Hole In One Piston

Ric & Jul - Once the motor is torn down and the cylinders are measured for wear, you will know how many cylinders need to be bored and which ones will simply require a hone job. <br /><br />The most important thing is to figure out what caused the problem. Keep in mind the hole in the piston is a RESULT - not the cause. <br /><br />Tell us a little more about the boat. How often is it used? How long does it sit without being used? What was the top rpm the motor was capeable of? What fuel and how old was it? What spark plugs? Please be very specific!<br /><br />Tell us ANYTHING that relates to the motor. IE - Were new plugs installed just before this happened? Anything that will yield a clue as to the cause so it will not happen again to the fresh motor.<br /><br />Good luck!

 

[Capt Ken]

Re: 1999 115 hp Johnson Hole In One Piston

Those old in-line sixes were bad to melt the #2 and #3 pistons. Want one for parts. Been hanging on the rack for years and haven't been able to give it away.

 

[lorax]

Re: 1999 115 hp Johnson Hole In One Piston

Thanks for the responses. I hope I didn't divert the topic too much from Ric & Jul's question.<br /><br />I'm interested in the emphasis you guys are putting on locating the cause of the melt down. In the case of my ol inline what do you do after you've cleaned carbs, checked timing, replaced fuel pump, H20 impeller and in my case even the ignition trigger?<br /><br />I'd like to fix the motor and sell it.(I don't mind working on them) but I don't want to screw somebody by selling them a motor that may well implode shortly after they fire it up?

 

[Hooty]

Re: 1999 115 hp Johnson Hole In One Piston

lorax,<br />Usually, the only three things that hole a piston are too much timing advance, too lean a fuel/air mixture and a carboned up piston. Take care of those and you should be o-k.<br /><br />c/6<br /><br />Hooty