40 Kohler questions?

**Stackem** · 03-17-2009, 03:49 PM

I've got a Kohler 40 hp on my fan rig. I use it for bowfishing. On the 1st crank up I have to choke it, like all engines, because it is cold. I can run it say for an hour or so, cut it off, and try to recranck it. It want crank without chocking it again? Can anyone tell me the problem. Thanks.

**Stackem** · 03-17-2009, 04:06 PM

Here is a picture of my rig. I'm running a 40 Kohler w/ a 1.69-1 reduction and a 56" B-series Power Finn prop.

**Papee** · 03-17-2009, 07:52 PM

It's sitting pretty high, maybe it's losing prime. I put a pump ball on mine and just pump it a few time before starting. Just a thought.

**Duane Scarborough** · 03-17-2009, 09:29 PM

Stackem,

That's a nice setup. How fast will it go sideways? Only kidding, I know how it works. But I am interested in the front platform. I could put the boat I'm building on the front platform.

What do you use this boat for?

Thanks,

Duane

**Stackem** · 03-18-2009, 08:14 AM

The boat is used for bowfishing. The fan will rotate 360 degrees. It is drivin by cable and sprocket from the front console. It is setup on a 1:1 ratio. Where ever the front steering is pointing, is which way you go.I have a Holley low pressure fuel pump w/ a holley regulator and guage to get the fuel flow to the engine. The regulator is set at about 1.5-2 psi. Seems like there is a carb issue, because I have to give it very little choke to get it started. It is just a pain to have to go to the back every time I want to crank it. I've got a key switch at the engine and on the front console.

**Stackem** · 03-23-2009, 12:05 PM

We don't have any engine goroos out there? Anybody have a clue what the problem might be?

**Wildfowl** · 03-23-2009, 01:51 PM

If you have fuel to the carb than I would say most likely you are running a little lean...not enough to affect it when running but enough that you have to choke it to start. Even the 40hp do not have much vacuum so a little bit off can mean a lot. Those engines are measured with water vacuum not mercury vacuum.

Could be a couple of things...might be as simple as stale gas or even some laquering in the carb/intakes. If there is not a physical obstruction (debries) making the engine lean than try some carb cleaner like seafoam and run it through. That could be all you need.

You might also have an air leak post carb sucking in air causing it to be lean.

Kohler's web site has a tech - trouble shooting tab with a handful of suggestions as well.

Good luck with it...I know I would not have much tolerance for having to run back and forth...UGHhhhhh!

**chuckitt** · 03-23-2009, 04:06 PM

Hey Stackem, Have you checked the Spark Plugs to see how they are running? That will give an indication of what might be wrong. Is the Governor disconnected. We don't use the governor on the mini airboats and when we run them wide open, it would run too rich so the plugs could be blackened with carbon and that could make it hard to start. After we done some carb mods, we haven't had any problems.
Thanks, Chuck

**Duane Scarborough** · 03-23-2009, 07:29 PM

Stackem,

I'm certainly not an engine guru, but have you thought about adding a choke solenoid so that you can "pull the choke" from up front with the push of a button?

Duane

**buster** · 03-23-2009, 09:06 PM

I have a JD lawn tractor that has been "cold blooded" like that for the nine years that I have owned it. Seems like I always have to hold the spring loaded choke with one hand, and steer with the other for the first two minutes every time I start it. So far nothing we have tried has helped. I think some engines are just naturally cold blooded! Good luck with it!
Dave