23yr old Honda Harmony 215 rebuild or replace?

[javjacob]

Not a bad idea to check it out first. I wonder how many hours these air cooled single cylinder Honda motors are good for? I was thinking 2,000 hours? Possibly more?
If the cylinder is wore you can have a engine machine shop bore and hone it for around $50 but you will also have to buy a new over bore piston and rings, not sure what that would cost.
Did the motor get like this over a long period of time or rather quickly? Also how often do you change the oil?

 

[mrntd]

I figured if the cylinder is bad the piston probably isn't very good either.

I changed it last spring and went to do it this year and noticed it was really low. It has not been like that before when I changed it.

 

[reynoldston]

Not a bad idea to check it out first. I wonder how many hours these air cooled single cylinder Honda motors are good for? I was thinking 2,000 hours? Possibly more?
If the cylinder is wore you can have a engine machine shop bore and hone it for around $50 but you will also have to buy a new over bore piston and rings, not sure what that would cost.
Did the motor get like this over a long period of time or rather quickly? Also how often do you change the oil?

The machine shops in you neighbor hood are a lot cheaper then where I live. They wanted over 100 dollars for the last one I priced. Its become a lost art to have a small engine bored around here because no one will do it any more. It is just cheaper to replace the complete engine.

 

[javjacob]

That sucks, there is a engine shop here that only does engine work. They build a lot of motors for the local circle track and drag racing guys. Last time I had a single cylinder small engine bored and honed they only charged $40 but that was about 10 years ago. Might be $50 or $60 today.

 

[reynoldston]

That sucks, there is a engine shop here that only does engine work. They build a lot of motors for the local circle track and drag racing guys. Last time I had a single cylinder small engine bored and honed they only charged $40 but that was about 10 years ago. Might be $50 or $60 today.

That is just the problem we have here, they just want to work on race car engines. They just don't want to reset up to work on small engines. As I said rebuilds on small engines is becoming a lost art because of the cheap Chinese engines flooding the market. As a small shop its just not worth my time to rebuild a engine anymore. Hang on to what you have because we don't have it here anymore. The last time we needed some work done on a farm tractor engine it took them the most part of a year to get it done and it wasn't cheap. The racing engines come first much less a 40 dollar lawn mower engine bore job. Then you need to find oversize pistons and rings in which nobody sells anymore. Its a complete new reset up for a small engine is the reason for the high cost. Most shops around here are charging around 100 dollars + per hour. You are also talking about 10 years ago so you might want to recheck them prices. If the OP can get his engine rebuilt for such a low cost I will say do it for sure because it will be a lot cheaper then a 700 dollar new mower.

 

[Saril]

I have a 1996 Honda Harmony HRM215 that was suffering the same thing as you. It was getting lower and lower on power and would stall easily in tall grass. I thought the motor was about wore out. I tried cleaning the carb good too thinking maybe that would help but it didn't. I then bought a new OEM Honda carb which only cost $35 and now it runs like new with full power again. The old carb was just wore out and was robbing power from the engine.

Thanks javjacob - based on your comment I just ordered an OEM carburetor.

FYI - my 1999 HRB215HRX compression measured around 138 (psi) cold and 140 hot. I had to remove the exhaust valve lifter (easy to do) in order to get an accurate reading. Without the exhaust valve lifter removed it was reading around 50 - 60.

The 140 psi seemed too good to be true so I tried an older compression gauge and it read around 125 with a slow leak (gauge hose leak) so I'm curious if 140 psi is indeed possible.

My understanding is if the compression is good, the engine is worth saving and no need to worry about piston, rings, or valves.

I hope my understanding is correct.

 

[7394]

When the compression seems Too good, look @ the piston top to see how much carbon is baked onto it. That & the combustion chamber caked up w/carbon will raise the C/R

Just my .02 here, but I'd remove spark plug & looking at the crank snout underneath, have someone slowly rotate the engine & see if there is run-out on the crank. Ideally a mag base dial indicator would be best.

But you might be able to place something stable close to the crank & see if it runs true or is bent.

 

[Saril]

Thanks 7394!
Good point - I have never measured runout on a single cylinder engine. It seems like it would be hard to do with crank installed.
If the run out was significant to raise the compression, would the engine also vibrate excessively?

 

[7394]

Thanks 7394!
Good point - I have never measured runout on a single cylinder engine. It seems like it would be hard to do with crank installed.
If the run out was significant to raise the compression, would the engine also vibrate excessively?

If I understand your post correctly, your mower has a cutting blade bolted directly to the crank snout, Yes ? Remove blade & check for run-out.


Run-out is not gonna affect compression, but a heavy layer of carbon build up on the piston top certainly will.
Run-out can cause vibrations. Depending how bad, so will be the vibration.