Honda GXV110 smoking a little

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Mar 7, 2004
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453
Location
Southwestern Ontario
Picked up a 1983 Honda HRS21 mower with the GXV110 engine the other day. Previous owner said it had no compression and wouldn't start. Brought it home - spark plug was not seated properly, so I ran a tap in the threads to clean them, re-seated the spark plug and had lots of compression. The carb was filthy - gave it a good cleaning and the mower started right up. I changed the engine oil with Valvoline conventional 10W30. I think it is burning a little oil - and it gets a little smokey when cutting up hill when the engine is under more strain.

The manual recommends 10W40 for all-round use, with 10W30, straight 30 and 20W50 also shown for various ambient temps. I was thinking of using the 10W30 as a flushing oil and then switching to a heavier oil to see if the smoking lessens. Do you think a heavy weight oil like 20W50 and an additive that helps with engine smoking issues would be too thick? Any ideas would be appreciated.
 
it's 37 years old and probably worn out and no special oil routine will help at this point. But oil is cheap and you have little to lose so I'd use PYB and see if it helps. A piston soak might be beneficial, who knows.
 
If it's gunked up and not worn out, it might be worth pulling the plug, pouring in your solvent of choice (I'd go with Berrymen B12), and let it soak on and around the cylinder overnight (longer is better). Just make sure to pull the string without the plug to blow out any residual chem, put a small amount of motor oil in the spark plug hole and then fire her up and let idle for a while. After this, change the oil and see if things have improved.
 
Originally Posted by gathermewool
, put a small amount of motor oil in the spark plug hole and then fire her up and let idle for a while. After this, change the oil and see if things have improved.



???Why....? If that is really needed.....for a whatsoever reason.....would not be 2T oil a better choice?

I would check also breather element!!! Maybe it is stuck and that engine is not breathing.....
 
Some of my engine manuals say to add a small amount of motor oil through the plug hole prior to storage. I figure a SOLVENT soak would leak past the piston and flush away any residual oil from the cylinder wall. Adding a small amount of ANY lubricant after the solvent soaked, but prior to starting is likely wise and hurts nothing. I just gave one example.
 
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Mowed the lawn (about a 1 hr job) today. Added about 2 tablespoons of STP stop smoke oil treatment to the VWB 10W30. Also added some Motomaster small engine fuel treatment to the gas tank. Engine runs great with lots of power. When it gets a little workout like a hill or deeper grass, it starts blowing some smoke out of the muffler. Checked the oil level after the job and it seemed normal. One thing I did notice is the oil had turned significantly darker - not sure if that's the STP additive. I think I'm going to do one more grass cutting and then change the oil with 20W50.
 
You could try running some Seafoam or MMO in the gas to help clean out the carb, you didn't mention if you cleaned out the tank or not and with the carb. being in poor shape then I would think the tank would need some attention as well.
 
Originally Posted by Merek
You could try running some Seafoam or MMO in the gas to help clean out the carb, you didn't mention if you cleaned out the tank or not and with the carb. being in poor shape then I would think the tank would need some attention as well.


I was thinking about Seafoam before I put it away for the Fall. And yes, the gas tank was cleaned out.
 
I pulled off the lower end cover to expose the crank, connecting rod and you can see into the bottom of the piston (don't even have to drain the oil to do this). Engine has sludge. It's not a sludge monster by any means, but it's there. I removed as much as I could by hand with a plastic scraper. The rest will have to cleaned by engine oil. I'm going to leave the SuperTech 20W50 in for several mows then look at a quality detergent synthetic.
 
Is it possible the oil is slightly overfilled? If you fill it based on the oil volume indicated in the manual, it will be overfilled and burn oil (ask me how I know this!). My GCV160 manual states oil capacity is 18.5 oz but 14 oz fills it according to the dipstick.
 
Is it possible the oil is slightly overfilled? If you fill it based on the oil volume indicated in the manual, it will be overfilled and burn oil (ask me how I know this!). My GCV160 manual states oil capacity is 18.5 oz but 14 oz fills it according to the dipstick.

Good call man! I'm a oil level junkie, so all my machines are up to the full mark. I tilted the mower forward and drained a little oil. Smoke has stopped! Now the oil is not right up to the full mark, but at the half-way point. Oil is about a centimetre below the fill line as per the sticker on the block.
 
Sounds like you saved one. My only thing about mower oil is to check before using. My most recent roadside rescue is a 4 stroke Lawnboy. It came to me with good looking oil on the stick. I've used it 3 times so far and level hasn't changed. For a 20 something Tecumseh flat head, it goes great. Maybe next spring I'll change it 😃
 
If it has sludge in it I recommend running a synthetic HDEO, I really like the Delo if you can find it up there but Rotella would work equally as well. I'd go with something 10w30 or 15w40 along with short intervals. If it takes you about an hour to mow your lawn I'd change at least once a month guessing you mow one day per week. I think most small engines recommend 50 hr oil changes without an oil filter but doubles to 100 hrs if it has a filter.
 
Sounds like you saved one. My only thing about mower oil is to check before using. My most recent roadside rescue is a 4 stroke Lawnboy. It came to me with good looking oil on the stick. I've used it 3 times so far and level hasn't changed. For a 20 something Tecumseh flat head, it goes great. Maybe next spring I'll change it 😃

To me, a Lawn-Boy without a 2-stroke engine is just not a Lawn-Boy.
 
The de-sludgification continues. Pulled the crank cover off again to see how the cleaning was going. The upper areas are much cleaner and a lot of the gunk had settled into the lower areas and valleys. I did a little more scraping of the really crusty stuff with a plastic pick and it came off a lot easier than the first time. So, out goes the SuperTech 20W50 and in went some full synth Motomaster (Shell Canada) 10W30. Pics attached.
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As author have suggested.....use a tad of two stroke oil...

...but it seems that you are already late...
 
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A little update. I decided to drain and clean the carb before putting the mower away for the winter. Upon tearing it apart, I noticed that I had missed removing the main nozzle which sits underneath one of the main jets the first time I cleaned the carb. The nozzle was covered in dirt. I don't even know how the mower ran as it was completely clogged. Gave it a good blow out with carb cleaner and compressed air and went through all the tiny holes with some fine wire. Re-assembled the carb and fired up the mower. Wow, started even easier and runs much smoother. And to my amazement, all the smoking is completely gone. Pulled the crank cover again to check on how the synthetic oil is making out with the remaining sludge and it is almost completely gone.
 
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