G9 crank but no start, need some input

[mr_camera_man]

Got a new-to-me G9, just acquired last week. Looked like it hadn't been used in a while, but started right up with a jump start and used it extensively last weekend. Came back to the campground this weekend and... nothing. Cranks, but does not start.

Here's what I've noticed so far:

Spark is good
Don't have a compression tester, but feels strong enough on my thumb?
Fuel pump is pumping
Starting fluid doesn't help, including sprayed straight down into the cylinder
Backfires when choke is applied
Spark plug smells slightly gassy but not really wet

Signs point to carb, except for the fact that it ran perfectly fine last week and seems to have shut off like a light switch. Gas that came in it appeared good and smelled fine. But maybe something dislodged when it was running last weekend and clogged somewhere? And wouldn't starting fluid help if that was the case?

I've read some other posts here that have said the CDI box could be the problem, even if it's getting spark. Should I be looking at the CDI box as well?

I've had nothing but bad luck trying to rebuild carbs, so I might throw a $25 Amazon Chinesium carb at it and see what happens.

What else should I be looking for? Of course I didn't bring my trailer down to the camper this weekend, so I can't bring it home to work on it this time.

[CP241]

Skip the China carbs. Clean the original mikuni.

There’s a lot of things you can check easily, but not from where you’re sitting now lol.

Pull the valve cover off. Check valve lash. Should be .004 for both valves. If it’s loose sometimes a push rod will fall out.

What color is the spark?

Make sure the airbox lid is completely sealed tight. Even the smallest leak can make it not run.

If you remove the carb be very careful tightening it back up. The plastic spacer between the carb and the head cracks *very* easily

[mr_camera_man]

Spark is bright bluish-white. Airbox is all sealed up tight, with all original hoses in tact. Got lucky in that this one appears to be un-messed-with aside from some simple headlight wiring.

Valve lash is on my to-do list for the next time I get back to civilization.

"Clean the original Mikuni" will likely mean "after much frustration, take a small baggie of parts to a pro and pay hundreds of dollars". If nothing else, I may get one of the Chinese ones to have as a spare when that all goes wrong.

[CP241]

Also, does it have the lid over the gas cap? If not, And if it spent a significant amount of time outside, the rain and dew tends to pool on the gas cap and funnel/deep in through the vent in the cap due to the shape and design of the gas cap. So if it rained while at camp and that lid is gone, there’s probably a lot of water in the tank.

You can buy replacement lids on Amazon for about 12 bucks. The screws are usually hella rusted out so I just zip tie them on and they work just fine.

And if your spark is blue and consistent I wouldn’t worry about the ignitor or anything. It’s something else

[mr_camera_man]

Yes, it does have the lid over the cap. It was missing the tank vent when I got it, and I replaced that today. Good point, that could have led to some condensation in the tank while it sat over this past week, there was some rain and humidity. I had drained the bowl today and there were a couple of times while the fuel line to the carb was disconnected and dumping gas while I was troubleshooting, so I'd think that would have cleared out whatever water was in there? But I'll bring a bottle of Heet down next time and see if that helps.

[raydhd]

I really wonder about spark since it doesn't run on starting fluid. To me that kind of eliminates a fuel issue. Have you tried a new spark plug ? Sometimes a plug will appear to be OK in a spark test BUT not good enough to run the engine. James Condon has had this happen a couple of times on his youtube generator fixing threads.

[mr_camera_man]

Yes, tried a new plug. Won’t start with the new one or the old one. But it’s a bright spark and it gives me a decent jolt if I hold it.

[CP241]

Disconnect the fuel line from the carb and put it in a mason jar. Crank the engine for a while and fill it 1/3 of the way or so and then let it sit for a few minutes. The water will settle to the bottom of the jar and be pretty obvious.

And I agree with ray it should run off the spray but its worth ruling out the easy stuff first. Nothing is worse than tearing out your hair (or what’s left of it) for something stupid like bad gas. And you just bought the cart so have no way of knowing how old the gas is that’s in it or if it’s got water. I can post a picture tomorrow of the gas that was in a G9 I recently bought. Crazy thing is, it actually ran. Just not particularly well lol. I couldn’t believe the amount of water that was in the tank when I drained it.


Not all was lost. It works great for lighting yard trimmings in my fire pit

[raydhd]

One other note here. My HD cart passed the finger test for compression BUT with a gauge on it reading was about 60 psi. With a 4 stroke LOW compression could be as simple as valve lash or some other valve issue. The 2 times a cart wouldn't run on spray was the low compression on the HD cart and a bad plug in my clone powered G 14. On the G2-14 engines there have been several cases here where a push rod dropped out causing low compression. Easy enough to pull the valve cover and take a look if all is as it should be.

[mr_camera_man]

Ok, no water in the gas at least. Looks like next time I have my trailer, I’ll bring it home to civilization and dive in to the carbs and valve lash. It’ll be a little easier to get a loaner compression tester from autozone when the closest one is down the street and not an hour away. Thanks!