Solved: Honda Lawn Mower (Model HRX217HYA) with GVC 200 Engine and Automatic Choke Hard to Start

In 2022 I bought a new, fancy, Honda lawn mower. I decided I needed something self-propelled and had a clutch so I wouldn’t have to restart it every time I had to stop and pick something up out of the grass.

This lawn mower has been a total bust. It was hard to start from day one. The retailer blamed the gas, which was nonsense. I did some research and these mowers regularly have issues with their automatic chokes, mainly due to it thermowax choke actuator. I detailed replacing the thermowax here.

By the time I replaced the thermowax, it was warm enough in the season I couldn’t really tell if the problem had been solved, but by the end of the season, clearly it had not.

Last season, on the last cutting of the year, it was quite cold and it took about 15 pulls to get the pile of crap running. I was not pleased, to say the least, and decided I was just going to have to get rid of it. Every honda engine I’ve ever had (generator, pressure washer, motorcycle, and auto) has been excellent. So this mower has been a true disappointment.

Last month I stopped to visit a friend who repairs garden tractors for a living. I discussed the issue with him. He was familiar with the thermowax actuator and said to check all of the linkage and be sure it was working before just scrapping the mower.

This morning I took a look at the motor. I started by taking a picture of the choke butterfly valve. To me, it is not closed far enough. I sent the picture to him, and he confirmed it definitely was not fully closed. Aha! At least there clearly an issue that might be able to be fixed.

I removed the carb and played with it. Clearly, the valve was not closing all the way, but there was nothing wrong with the linkage. The pin in the thermowax actuator was fully retracted, but the butter fly valve would open as I placed the carb back into position. It was like the thermowax actuator was just too long:

I sent this picture to my friend who said it definitely was sticking out too far and sent this video to me for reference:

I had direct sunlight and could see into the hole and I didn’t see anything in it, I just couldn’t get the actuator to go far enough back.

I had originally noticed some kind of rubber thermal putty around the actuator, but hadn’t thought any more about it. On further examination, I realized that putty was in the back of the hole – it looked enough like the head under bright light I didn’t see it at first.

I started picking at the putty with a small screw driver and was able to get a lot of it out, especially from the bottom of the hole where it was causing issue:

With the putty out of the hole, now the actuator fits properly:

and the choke butterfly valve fully closes:

 

NNote to anyone having this problem: above is exactly how the butterfly valve should look when the engine is cold. When this problem started, I tried repeatedly to find a picture of what this valve should look like closed so I could verify I was having a choke issue. I never found a clear picture and was never quite sure if the choke was the problem until now.

I fully reassembled and put in fresh ethanol-free fuel – I had let the engine burn out the remaining fuel end of last season.

Even with a dry carb, the mower started in 3 (moderate) pulls at 55 degrees F. Looks like the operation was a success! Tomorrow I’ll try another 50 degree start now that fuel is in the carb bowl. I’m betting it will start on 1-2 pulls rather than the 8-15 it has been taking when it is this cold.

Update

Next morning I tried another cold start in 46 degree F ambient temperature. Started on 2nd try. I can definitely live with that!