Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have here a piston connecting rod that has just a little too much play in the bearing/bushing that connects it to the shaft.  Is there a bearing/bushing that can be replaced or does the whole connecting rod/shaft assembly need to be replaced? This is off of a Honda 5hp horizontal shaft 4 stroke engine that belongs in a honda single stage snowblower (HS520). 

Looks like I have some homework to do. 
1) remove the bolts holding the connecting rod to the shaft (didn't do it earlier because no manual on retightening). There is definitely some play here.
2) check for nicks in the small teeth of the big gear on the crankshaft.
3) check for wear on the crankshaft.
4) double check the bearings on the end of the crankshaft (should be no lateral play)
5) check on replacement engine costs.
6) check for scuffing on the piston skirt.
7) locate a manual (I did find the parts manual and owner's manual, just not the shop manual)
8) get some prices on gaskets, rings, pistons, yamabond, and a connecting rod
9) take a deep breath.

Here's what's what:

1) remove the bolts holding the connecting rod to the shaft (didn't do it earlier because no manual on retightening). There is definitely some play here. 
Discovery :  See the photo of the bearing surface. The aluminum connecting rod bracket shows wear but the crankshaft looks fine to the untrained eye. (Please disregard the dirt and grit,  the open engine was left outside in an open box and was covered by falling leaves for a few days).
The fit  is not tight.
2) check for nicks in the small teeth of the big gear on the crankshaft.
Discovery: The teeth are fine and show no signs of nicks.
3) check for wear on the crankshaft.
Discovery: This is the first crankshaft I've ever seen in my entire life.  That said, it looks like its been heated by the friction of the spinning connecting rod but it does not appear to be worn down.  The aluminum connecting rod bearing surface does appear to be worn down.
4) double check the bearings on the end of the crankshaft (should be no lateral play)
Discovery:  I slid the cramkshaft back into the bearing.  The shaft fits very snuggly with no noticable play. 
5) check on replacement engine costs.
Discovery: I called a few internet place and got prices.  The best I could do new was $230 .  The engine is a Honda GC160 5hp.  Several vendors told me that honda snowblower engines are constructed differently from other GC160 motors and that they are not interchangeable.  They said something about the cylinders being different but to be honest the explaination was over my head.  Ebay has GC160 engines but Honda mass produces these for so many different applications from compressors  to power washers, to go carts and water pumps that its difficult to know if you are getting an engine with a compatible output shaft .  Honda made 7 different crankshafts for this engine.  Ebay prices run around $120 delivered for  a lightly used motor. Harbor Freight sell a $150 honda knockoff but its 6.5 hp. 
6) check for scuffing on the piston skirt.
Discovery: The piston does have scuff marks on it. I tried to take a picture that would adequitly show the scuff marks.  I would be interested to know if these scuff marks are just normal routine wear or a telltale sign of some other issue.  See photo below.  Note: There is no verticle play in the piston/connecting rod juncture. There is horizontal play. 
7) locate a manual (I did find the parts manual and owner's manual, just not the shop manual)
Discovery:  A vendor in California  will mail me the manual for $30.  .They have to order it from a distributor first. The price seemed  reasonable.
8) get some prices on gaskets, rings, pistons, yamabond, and a connecting rod
Discovery: 
Ring set (13010-ZL8-003) $19.06
Piston (13101-ZL8-000) $34.38
Hondabond (Used as gasket material for cylinder and cylinder head)  08717-0004 $6.50 
Connecting rod (#13200-ZL8-000) $39.36.  
9) take a deep breath.
 I opted for a beer instead.

Here's a 5 h.p. Honda GC engine at Small Engine Warehouse for $170.00.  You're looking at close to $100.00 to fix the old one.  If this engine is suitable, the decisionis a no brainer to me. 

http://www.smallenginewarehouse.com/product.asp?PN=GC160QHAF-TO&desc=Honda%20Engine%20%205hp%20Horizontal%203/4"x2%205/16"%20Keyed%20Shaft,%20OHC,%20Stationary%20Throttle

borat wrote:

I called and spoke with a salesperson at Small Engine Warehouse  ( 800-321-6725) about this  motor ($190 w/ship) and they told me that it was not a suitable replacement for a honda snowblower GC160 engine.
They explained to me why not but to be honest the answer was too complicated for me to really understand.  They said to check back another time because they get engines in all the time.  .  Is there a less expensive online parts dealer?  I understand that Honda keeps a tight lid on parts distribution.  I did find a place (Tulsa Engine Warehouse) that had aftermarket parts for less.

	PISTON RING SET	Piston Rings		$9.00	$9.00
	PISTON ASSEMBLY	Piston		$21.00	$21.00
	Standard Connecting Rod	Connecting Rod		$10.50	$10.50
Estimated Shipping (Best Way)					$8.95
				Total	$49.45

Your connecting rod doesn't seem to be worn much at all which is odd given the
condition of the bearing surfaces on the crankshaft.  I suppose the marks there
are deposited aluminum but there doesn't seem to be much gone from the rod.

What does the inside of the cylinder look like ?  The piston is pretty scuffed up so
it must be pretty loose.  I'm not sure but I doubt your cylinder has much of a sleeve
(probably just some sort of chrome coating ?) so any wear to the cylinder wall could
be costly.

Apart from the 100$ or so for parts, a minimum I'd say, you should also figure
in your time and experience.  Do you have a torque wrench, for instance ?  Have
you reassembled small engines before ?  Not trying to discourage you but an
engine in a basket can be a bunch of trouble.

How much would a proper engine from a Honda dealer cost ?

Paul

pvrp wrote:

I have a torque wrench.  I have never reassembled a small engine before and I'm not an engineer.  I have taken apart dishwashers, washing machines, and small electronics.  I may have bitten off more than I can chew with this project, so don't feel that your words are taken as "trying to discourage."   When I was 15 my dad took a small engine repair class and completely disassembled a tecumseh L head engine off of our ariens snowblower. The next few winters I had to shovel the driveway by hand. 
Here's a photo of the inside of the cylinder. One side is not as smooth as the other. This is the not-as-smooth side:

From the looks of the cylinder, the engine was either run low on oil or run in dusty conditions.   Being that it's on a snow thrower, I'd venture to say it's the former.   I personally wouldn't use that cylinder and being a Honda "GC" series, it doesn't have an iron liner.  Which means that it's pretty much shot.  You can check to see if it can be re-bored but doubt if it can be.  If the engine had been run low on oil, just about all of the other friction surfaces are likely compromised.  Don't want to burst your bubble but I'd say it's a lost cause.  If you decide to get a new engine, the Honda "GX" series are the industrial application models.  They have a cast iron liner and are supposed to be more robust overall. 

borat wrote:

This is good to know. No reason to waste my time.  I appreciate the input. I bid on new replacement engine that sold on ebay today, but lost it  at $140 delivered.  As far as replacement engines go, if I find a Honda GC 160 with a shaft that is the same length and keyed and threaded the same way will it fit?  Are there other parameters to look for?  

 I had thought about parting it out and trying to sell the gas tank, gas cap, flywheel, spark plug, recoil starter, Magneto / Ignition Coil, drain plug, timing belt, plastic cam, and exhaust.  I thought that the sale of these parts might  subsidize the replacement engine. 

 I may try to reassemble this one just for the experience.  If I reassemble this and it starts what will happen?  Will it explode or do anything dangerous? Putting it back together might be interesting.  Maybe not. 

So looking back on the demise of the engine, why would it have run low on oil.  New engines shouldn't ever really run out of oil should they? You are right, it would not have been run in dusty conditions. I'm at a loss to explain what might have happened. Why would the plastic cam wheel and timing belt have broken? (those are brand spankin new)

How bad are the scratches on the bore and crank journal?  As someone on this list once wrote, “can your run your fingernail across the journal and not catch it on bumps and ruts?   If there are no ruts you might get lucky and be able to sand off minor high spots and remain within spec.  You’d have to be very lucky. 

 

   The same for the bore.  Are they scratches or surface marks?   They look bad but again if you were lucky and no ruts then you could re-hone and see how close you are to tolerance limits.  How do you check?  HF sells a bore gauge set for $7. They have a digital vernier for $10 on sale.  The gauge compares well to a much more expensive Starett.

 

   The idea being it might be worth the $50 to get an education.  Rebuild the motor and see how it comes out.  You might get lucky on the first shot.  People on the list helped me out and my first motor actually ran well.  If it runs and sucks as a motor you’ll have made a big accomplishment.  It would be better to hack on this motor as a learning experience then learn on a much more valuable engine. 

 

   Harbor Freight has some decent engines.  I bought three last week at $109 each.  They come with a 90 day warrantee.  For 11 bucks they add 12 months so that will cover these motors over two snow seasons.  The warrantee is also transferable.  The HF motors are made in China by Lifan.  Lifan is one of China’s better makers of small engines.  They are a giant company making all sorts of motorized things.  I know their motorcycles very well and they are excellent.

 

   The HF engine is 6.5hp, OHV, cast iron bore, and low oil shutoff protection, arm throttle control but has holes for a cable, fuel shutoff and choke at the carb.  They are made in partnership with Honda so a legal clone and the parts interchangeable with Honda.  I have mounted a few on great older Ariens bodies. 

 

   One of these engines might be an option.  Lifan is a quality maker but who knows the actually quality of the model HF is selling. ?? We’ll see.  I spent 4 years in China and pretty familiar with their small motors so getting them was not a problem for me.

 

   If you did replace yours I’d still go with the rebuild if the scoring was not prohibitive.  Even just putting it all back together would be worthwhile.  It’s not as complicated as it seems once you wade in.

David

trouts2 wrote:

A finger nail does not snag on any of the scratches. The scatches on the piston and cylinder  are more like surface wear marks. The crank shaft is smooth as glass but darker in color.   My camera does not allow me to get much depth of field with the flash on. That's why the photos are so blurry on the cylinder.
I realize that I'm the only one that can really see/touch the damage. So I'm really the only one in a position to do a fair job of assessing the damage. Infortunately I have no knowledge of what I'm looking at.

I have a 15% coupon to harbor freight and they have a store near me.  I'm not sure how difficult it would be to size another engine to fit (even a honda clone).  I could take the old engine with me to the store and set them side by side.  This being a single stage blower everthing needs to fit inside a plastic housing.  That might also mean the end to the electric start and who knows what else.

As for putting it together.  I found an exploded diagram of the engine so i might be able to get it back together.  The shop manual would probably be a neccessity. Would I at the very least want to replace the old connecting rod ($20 delivered)?  I would need to find some way to clean everything really well. Not sure how I would do that.  There are small piece of grit everywhere from it sitting under the tree. (the owner was leaving it out for the rubbish).

 I would have more confidence/faith in fixing the engine if I had a better idea of why it failed.  Give the benifit of the doubt to the person that set it up before it left the showroom. It was full of oil.  In 3 years on a 14 foot driveway (I saw the driveway and the owner was as honest/respectable/conscientios as they come).  Say 16 storms a year, 30 minutes/storm, 3 years = 24 hours (total).  I cannot figure out what went wrong or why the plastic cam wheel would have broken. 

I think I'll sleep on it.