Need help my Honda 5518 tractor has engine problems

I have a 1995 Honda 5518 (gas engine) tractor W/midmounted mower that about 10 years ago broke down due to low compression in one cylinder. Initially when I got it, it ran ok, a short time layter I changed it over to a Hydrualic frontloader which required me to remove the mower part, after that it ran most of the time with the engine underloaded ( the frontloader uses a lot less power then the mower ). That I think eventualy unseated the rings in one of the cylinders if so I think the easiest fix is to remove the head and look for glazing in the bad cylinder. If that is the problem what would then be involed to fix it; get a new piston and rings, boar out the bad cylinder or hopefully just deglaze the cylinder? thankyou.

You probably should do a compression check first. Pull the head to see what the cylinders look like. If the cylinder is low on compression it may need to be bored oversize. Have your local auto machine shop to take a look. Hal

Is it only advisble to deglaze a cylinder if it's been boared and using a new piston and new rings
my engine has very few engine hours 250-300 and since this engine is liquid cooled there should be little wear.

Also I have an unused replacment engine except for one problem, it has a bent crankshaft that happend when it was damaged during shipping due to being poorly packed so if i replaced it with the crankshaft from the old engine (these only have two cylinders) would that be easier and cheaper do you think ?

I assume its missing on one cylinder? Did you diagnose it before you come up with this deglazing theory? Id check the simple things first, like no spark, etc.

I checked that myself that one cylinder does have low compression.
The last time I ran it if I could get it started it could run on two cylinders but it would run ruff.

Before getting into the exotic stuff like the glazing on the cylinder wall (only theorized), unseated rings (only a guess) and other overthought items, how about a bit of good old fashioned DIAGNOSIS!!!

An engine needs three things to run:
1) Compression
2) Spark - and at the right time
3) Fuel/air mixture.

Have you checked compression? Have you checked both cylinders for spark and Timing? Have you checked to see that both are getting fuel?

Just suppose that you tear down the engine, re-ring and deglaze the suspect cylinder, and put it all back together and have the SAME PROBLEM??????

Start with some basic diagnostics. I would first check for spark at both cylinders. If the spark checks ok, check timing. Many 2-cylinder engine have separate ignition for each cylinder. In that case, each cylinder is timed individually.
If spark and timing are OK, examine the plugs. They should be a light tan in color. If one is dark, wet, or white and dry, it would indicate a fuel or misfire problem.
A compression test would come next. A manual and following manufacturer's instructions would be helpful at this point. Engines with compression release might be a bit difficult to get a valid test on.
Seems a bit extreme to proceed directly to overhaul procedures to track down a misfire.....

Have you checked valve clearance? Could be the cause of low compression if a valve isn't closing completely.

Seems kinda strange to me that it would "unseat" the rings on one cylinder only, in fact, I heard of seating rings, and have seated them myself, but this is my first encounter with the term "unseated" rings. I would check for a hung valve, bent push rod, dented valve cover, sort of repair.

Most lawn mower shops have a jig for straightening a bent crank, without taking the crank out of the engine. Should take less than a hour labor.

Crankshaft bent in shipping? Wow, someone should get an award for that! LOL

Seriously though, before tearing the engine down, need to determine why the cylinder has low compression. Run what's called a "cylinder leak down test". It's simple, but you need an adapter to connect compressed air to the spark plug hole. Best to remove the rocker arms first so the valves will be closed. Listen for where the air comes out.

I doubt the problem is going to be rings. If it had bad rings, there would have been other problems, like oil consumption and oil blowing out the crankcase breather. Most likely there is a valve problem, or something as simple as a bent pushrod.

I would be very careful combining the 2 engines to make one. Honda's are known for "custom fitting" engine components, such as rod bearings, pistons, etc. Good practice for getting factory clearances right, bad for trying to repair them later.

I would doubt that the rings became unseated, would expect a valve or head gasket issue first.

I think what I'll do is order a new crankshaft that I'll put in the replacement engine, then use that engine in the tractor.

It does't uses push rods it's an overhead cam engine. http://www.hondalawnparts.com/oemparts#/s/HONPE/H5518/

In the picture is my spare engine and you can see the exposed flywheel, when I recieved it it came in the original box but without any packing inside except some rags which is how the crank got bent.

Thanks jimg.allentown I did'nt think of the compression release might give a bad compression reading.

Thanks casecollectorsc I'll check the valve clearance.

And thanks to everbody else for your helpfull comments

Here is a picture of my spare engine.