Honda HRX Mower Hard Starting and Smoking

2009 Honda HRX217VKA, Ser # MAGA-1531212
Engine Ser # HAA-1781839 HY9 (? not sure if last digit is a 9)

Has run with no problems until last year (Mar 17) when it became very difficult to start. Took it into local very reputable repair shop. They did major tune up, and cleaned carb and tank. Mower ran OK for summer. They advised me to start it up for few minutes once per month during the off season. I did that with no problems.

BUT, the first time (yesterday) that we tried to start it to cut the grass, my tenant a 35 yr old man, could not budge the starter cord. I pulled on it to find that it seemed like the engine was seized up. I am a big guy so I really put some pull into it, it "broke loose," and started up on this pull.

I noticed that it smokes (white) for a minute or two after starting up. Also, if I stop and restart it, It starts back up easily but it backfires every time. I checked the oil and it looked brand new and at the proper level. So we cut the grass.

Today, it started right up but it still puts out the white smoke and backfires on restart.

Any idea of what's going on here?
Thanks much.

Might just be some water contamination of your fuel due to condensation and engine internals rusted a bit in storage. Are you storing it in an unheated shed?

I am not sure why they would tell you to start it every month in the winter as that can definitely lead to water (moisture) to get into things. You should be able to run the engine and tank dry before you put it away for the winter and then at the start of the next season, remove your plug, put a couple of drops of clean oil into the top of the cylinder and fill up with FRESH, NEW gas, turn fuel valve back on and it should start right up. As for your specific issue, you may need to have the carb removed and cleaned out again. I once made a mistake of tipping the mower over with the carb down instead of up and oil got into the carb, which really messed things up. I had an HRX for 7 years with absolutely no issues other than my mistake! Hopefully it is nothing bad. You could also try using some Seafoam to try and clean the engine out as well. There are some videos online of this if you want to do it. I have personally never tried using it directly into the carb as some videos will show you, but I have added it to the tank when I felt like my machines were running rough and it seemed to help. Now I just run ethanol free and I seem to have no issues. Good Luck.

Mike

Mike,

Mower has been stored in same shed, summer and winter, for 9 yrs with no condensation problems that I know of.

Thanks for your detailed response. I am thoroughly familiar with the winterization process you described, but frankly, have forgotten to do it for the last couple of winters. Or I may have just skipped it because we only go about 2 months without cutting the grass. Will likely do it from now on. The dealer's logic for starting it up was to run gas through the carb in the hopes of minimizing crud/varnish from evaporation etc. I DO use ethanol free gas. The dealer explained this will help but absolutely will not stop the problems with modern gasoline and its other additives. (and he was NOT trying to sell me Trufuel!)

I talked with the dealer yesterday who was gracious enough to help me over the phone. Based on the symptoms I have described (daggone it, I forgot to say that the oil smells like gas) he thinks that gas is leaking down into the cylinder when not running....maybe a defective carb needle. Someone else on another forum said the same thing. I think this would explain the engine feeling "seized" because maybe there was no oil to lube the piston / rings. This seems like it would also explain the white smoke for the first minute or two. I do not know about the backfiring.

BTW, last year the dealer told me that since the carb was about 8 yrs old, it will be due soon for rebuild or replacement.

So here is my plan. First I am going to try to determine how difficult it is to remove the carb. Any advice on this? I am going to inspect/clean the bowl and the needle, OR I might just replace the carb, based on how much it costs. I have tried before and I will NOT attempt to install a rebuild kit.

I am guilty of using relatively old fuel, so I am going to stop doing that. Will continue with ethanol free AND additives, and keep fuel no more than a year. Will not use Trufuel in my mower, but I DO use it in my other 4 small engines. I never have to worry about gummed up carbs, and they start right up at the beginning of the season, even after sitting with fuel in the tank for 2-3 months. This for about 5 years now.

The engine feels seized because the cylinder get liquid fuel in it and as you know from High School physics, liquids can not be compressed.

Usually forcing the engine full of liquid to crank breaks a ring or two and blows the head gasket.

You distinctly said the oil was at the correct level.
If you have a leaking carb then the oil should have been higher.

No excuses on Hondas cause they have fuel taps fitted to prevent this happening.

Honda carbs are very suseptiable to blockage from gummed up old fuel.

I talked directly to a very knowledgeable Honda tech rep. He knew exactly what was happening and said I needed to rebuild or replace the carb. Have ordered a new carb for $42. Small price to pay to save a $5 -600 mower.

He also said to change the oil!