Good morning forum and thank you for letting me join.
I have recently purchased a used Honda Hr194 from the dreaded eBay.
On start up it bellows out what seems to be white smoke and it does smell like oil burning. It does calm down after a while but it never really goes away. On google search I found an article on the breather pipe potentially blocked but I have checked and blown this out and I couldn't see any difference at all.
My question to you guys is, is this and easy enough job to replace the rings and head gasket or does anyone have a good working engine that they may want to sell that I can pop straight on?
I believe it's a Honda GXV 120 that fits this machine. I popped into my local garden machinery store yesterday but they have told me to scrap it, they deem it to be beyond economical repair.
I do want to save this one way or another obviously with the help of you guys.
Any advice or info would be gratefully appreciated. 

Hi, and welcome to TGMF.

I guess these days it comes down to the cost of labour to do these jobs from a dealers point of view, and repair will probably cost more than you paid for the machine.   

It's a pretty straight forward job to fit new rings provided you are mechanically minded, and have the necessary tools etc. 

Those engines have always had the smoke on start up issue once they get a bit of wear in them. Rings can cure it if the bore is good, and not scored. Oil leaking up the valve stems can also cause this issue.   

Hi Mick thank you for taking the time to respond I do want this mower saved as I prefer the old stuff to the new mowers.
I'm probably going to have to take the engine off and see what's it's like inside.
I really wanted to try and find. A good engine and just plonk it on.
From what I can tell there seems to be various gx120 engines for sale on eBay and I'm not really understanding which one it is I need.

The thing with buying a (used) replacement engine off ebay is you could be buying one with the same problem, it is quite common for them to smoke on start up as I mentioned. Usually though the smoke disappears after a minute or so.

I'm hoping Tim  @Swissqp will pop in and offer his findings, he's rebuilt a few of these engines lately with the exact same issue. He's also been very lucky finding / sourcing replacement parts for these older machines that I thought were long obsolete. 

I did forget to mention something though. 

You say you bought the machine off ebay, I would give it a good run if not already done so, it might have been tipped up in transit, and accumulated some engine oil in the exhaust, this will smoke more as it gets hot, and will take a while to stop.  Also check the oil level is not over the full mark. 

Thank you Mick I do hope Tim comes on the scene and can offer some help I would like the engine rebuilt properly so I can salvage the mower scrapping it is not and option for me

fire it up and leave it running for half an hour, im betting same as mick that its been tipped up and the exhaust has oil in it. My Dad had one from new bought in 1984 and used right up until 2017 when it was stolen, it didnt use a drop of oil and it was worked hard throughout its life with him.

hi all I have let it run most of today although the smoke does clear a bit from the initial start up its not going away.

I guess I'm going to have to bite the bullet and get it the engine rebuilt.

   

Quote from: Mick on July 25, 2021, 12:02:27 PMThe thing with buying a (used) replacement engine off ebay is you could be buying one with the same problem, it is quite common for them to smoke on start up as I mentioned. Usually though the smoke disappears after a minute or so.

I'm hoping Tim  @Swissqp will pop in and offer his findings, he's rebuilt a few of these engines lately with the exact same issue. He's also been very lucky finding / sourcing replacement parts for these older machines that I thought were long obsolete. 

Hi all, yes, I am completely self taught and changing the rings on the GXV120 is straight forward even for a newbie. I did one just last week on a HR214 which was smoking badly. They react very well to re-ringing. Thankfully Honda have made the full service manual available here https://www.honda-engines-eu.com/documents/10912/31969/1550/923b4816-9e57-4be2-9d82-e6efa7a24394

Now for a few tips:

1. Before you start ordering parts check you can get your blade holder off the crankshaft easily. Use a gear puller if needed.

2. Remove any fuel from the tank and drain oil. Remove the drain bolt from the carb and remove any fuel. Remove the fan cover and recoil.

3. Remove the engine from the mower deck. You'll need to disconnect any cables (throttle and rotostop if it has it) and the drive shaft.

4. Remove the cylinder head. Remove the sump bolts underneath and gently tap with a rubber mallet to get the oil pan off. Remove the camshaft and put it in to the oil pan for safe keeping. Look at where the piston connecting rod. Mark the conrod and the piece that goes around the journal with a permanent marker before removing the two bolts. These parts must go back together the right way. I also mark the tappets and remove them.

5. Remove the piston and push it out of the head.

6. The most time consuming part is cleaning the gasket off the two mating parts of the cylinder and oil sump. I use gasket remover which you can get at Halfords. Also remove any carbon build up from the cylinder head and valves. Don't scratch the machined cylinder head surfaces. I also remove the valves and lap them.

7. I also hone the cylinder gently.

Make sure to get any bits out of the cylinder and oil sump - I use brake cleaner to do this.

8. Install the new piston rings and install in cylinder with the arrow on the piston pointing towards the valves (and the rings gaps set at 120 degrees from each other) using a ring compressor. Reattach the conrod to crankshaft bolts and torque 12nm. Install the tappets and cam shaft (lining up the timing marks) Install new gasket, put a little grease on the lips of the oil seal and gently reinstall the oil sump - bolt the two bits together. Same with the head gasket. Follow remaining steps.


9. Parts diagrams can be found at Lings Honda parts...you'll need new rings, new head gasket, new sump gasket and maybe a new sump oil seal. New ring code: 13010-ZE6-013.

Any more questions please let me know. Take your time, take lots of photos, use little sandwich bags for any parts you remove and label them.

thank you so much for the info im going to try and give this a go and see what happens

Morning All,


sorry its been a while I've finally taken the engine off the mower deck and am washing all the old debris off it ready for disassembly.
in the mean time I was wondering would anyone know if the gxv160 engine would fit straight on the mower I have they look the same all be it a new engine than what i have.
the rear pto is in the right place etc etc.

i have spotted one on eBay and if it fits would like to purchase it and that will get my mower going again and that will give me the winter months to repair the original engine which I would then keep for spare.

thank in advance

I'm not sure a GXV160 will fit. Did you swap out the rings?