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I have a Grasshopper mower with a Kohler Command Pro 25 and after it sits over night it starts hard. It runs prefect after I get it started. I usually have to put a little gas it the air cleaner to get it started. I've changed the fuel pump twice, added a check valve in the gas line to keep it from draining back to the tank and checked the solenoid valve on the carburetor, it's energizing. Is there a way to do away with that valve? I suspect this valve. I've read where some engines have and some don't. It will start good the rest of the day.

Thanks, Gene

Make sure the choke is closing all the way, because it doesn't take much gap to create hard starting. Also check to make sure that the solenoid is energized while cranking, because that has been an issue over the years with various key switch problems. You can also remove or clip the carb solenoid plunger if you want and can live with the possible after fire bang.

I would lean more toward a choke issue than the solenoid issue though.

ILENGINE said:

Make sure the choke is closing all the way, because it doesn't take much gap to create hard starting. Also check to make sure that the solenoid is energized while cranking, because that has been an issue over the years with various key switch problems. You can also remove or clip the carb solenoid plunger if you want and can live with the possible after fire bang.

I would lean more toward a choke issue than the solenoid issue though.

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The choke is working OK and the valve is energizing; I pulled it out and watched it and you could hear it before I pulled it out.

Thanks, Gene

How fresh is the fuel. I reason I bring this up is because with fuels today they tend to go bad quickly, and I don't mean varnish smell like crap fuel, but just deteriorated enough to cause starting problems when cold, but will start fine the rest of the day. A hard cold start issue has been seen with slightly off from fresh fuel even with EFI engines . So it may be worth draining all the fuel and run it a few minutes to get the fresh fuel into the carb and fuel system, and then try to start the next day and see what happens.

Just for S&G', make sure the solenoid valve (that moves), is NOT getting stuck /hanging up in the carb body itself.

You should be able to remove that moveable part, re-install the solenoid and see what happens...

As noted earlier, it sounds like your choke butterfly isn't closing FULLY. Especially if it's cold outside, it's even more important it's closing fully..

I treat all my gas in my engines that I don't run that often. I just mowed about a week ago and put in 5 gallons. It don't set to long before I run it. The choke is shutting off, awhile back before I gave it a shot of gas, I put my hand over the intake on the air cleaner. It's got a lot of suction, but didn't start, but just a little shot of does it. I live in Florida.

Thanks, Gene

It's obviously not getting enough fuel while cold..

I would still remove the solenoid just for testing at least.

IDK if there's any orifices specific for the choke on your machine. Some higher end carbs do.

If yours does, that fueling orifice sounds as if it's clogged..


BTW, what make stabilizer are you using? (I'm in SW Florida.)

I use Sta-Bil. I put it in the gas can when I go get gas. What is (IDK if there's any orifices specific for the choke on your machine. Some higher end carbs do.) I don't know. I did take the the solenoid out today, but won't know any thing till tomorrow. Does anyone have a link to one of these high end carbs.?

Thanks, Gene

drifter said:

I use Sta-Bil. I put it in the gas can when I go get gas. What is (IDK if there's any orifices specific for the choke on your machine. Some higher end carbs do.) I don't know. I did take the the solenoid out today, but won't know any thing till tomorrow. Does anyone have a link to one of these high end carbs.?

Thanks, Gene

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IME, I've used Sta-bil with POOR results... (Long story you don't want to hear)..

Anyway, many Yamaha Out Board engine carbs use a system ("Prime Start") that uses a solenoid bolted to one (or two) of it's carbs (Keihins I believe). When cold, the solenoid activates, opens (like on the bottom of your carb) and allows extra fuel to flow into the engine via orifices. There is NO choke plate.

There was just a thread (see below) about hard starting. That solenoid wasn't working and worse yet, the plunger was FROZE UP in the carb body!!

Post #4 specifically how it works, the froze plunger-post #19:
http://www.yamahaoutboardparts.com/...utboard-forum/213263-90tlrd-prime-start-issue

I started it two mornings now and it started right up!! Thanks a lot for all of your help guys! Gene

drifter said:

I started it two mornings now and it started right up!! Thanks a lot for all of your help guys! Gene

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So what was the actual fix???

Well, I guess I was so tickled it was starting good, I forgot to tell you what I did. I removed the solenoid and made a plate to cover the hole where it was. I installed a O"ring and put the plate in place and that did it. When I shut it off it stops like normal, no back fire. Works Good!

Thanks again, Gene

drifter said:

Well, I guess I was so tickled it was starting good, I forgot to tell you what I did. I removed the solenoid and made a plate to cover the hole where it was. I installed a O"ring and put the plate in place and that did it. When I shut it off it stops like normal, no back fire. Works Good!

Thanks again, Gene

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Excellent! Have fun!!