Problem with Kohler Command 26 EFI

[jdl]

Hi all,

Glad to have found this forum as a relatively new owner of a Max IV. I got it primarily to get to and from an off-the-grid cabin up in the Cascade mtns in Washington state. It has the nice snow tracks and all.

I'm having two issues and I think they're both probably straightforward, but thought I'd try to look for more input since I only have one shot per weekend to try to fix any issues.

Issue #1 - after sitting for a week or so, it starts up fine, then bogs down about 5 min into my ride. If I'm careful, I can usually stop and keep it from dying, wait a few seconds, then keep moving forward. I tried varying my speed, but that didn't seem to help much. The best solution seemed to stop and idle or go easy every few 100 feet or yards. After 15 minutes of running, it seems to get better.

Is this just an issue of the engine being cold? Any thoughts?

Issue #2 - at the end of the weekend, after it sat overnight, I added about a half quart of oil. Being an idiot, I may have added to much because I didn't look carefully at the line. It started fine, but then would die after 5 seconds of me throttling it. So I let it idle for 5 minutes and tried again. Same result. Each time it would run hard then the throttle would be unresponsive and die or almost die. From looking at other posts, I'm guessing it's that I overfilled the oil and now need to drain some oil, change my air filter and maybe even change the spark plugs. Does anyone have thoughts about whether I may have other problems going on? I'm running and storing this in below freezing weather, so perhaps there are other precautions that I need to be taking?

Thanks for your ideas and advice.

JD

[jdl]

By the way, I had to repost this since the website deleted everything within the past 2 weeks. If you posted a response for me, can you please repost? Thanks!

[cobalt]

Hi.

Interesting problem.

To be honest it sounds more like a fuel problem.

#1: I would check the fuel line and any inline fuel filters for water contamination.

Even if you change the gas the water could still be floating on the lower part of the filter(s) and when you throttle up it could end up mixing with the fuel.

This happens often when any motor is stored below 0 degrees C.

#2: It could also be a vapour lock. Since you problem happens when you throttle up more.

Try opening your gas tank cap a to let some air in then close the gas cap about half way. Then give it a try to see if it bogs down.

Good luck.

[hydromike]

Hey JDL...

Sorry getting back to this topic so late. So, we've established that you have a Kohler EFI 26 horse in your Max IV. I'll need the Max Gurus to tell us for sure if the 26 EFI ever came as standard equipment in the Max IV to begin with. The reason being, is that fuel pump placement for these EFI engines, as I've found out, is critical. If it's a retrofit (which would be an awesome retrofit, by the way), there is a chance that pump placement isn't optimal. I had this problem on my EFI Chief, and suffered from the very similar if not identical symptoms. The EFI pumps used by Kohler don't pull very well at all, but push incredibly well. My pump would actually introduce a very small air bubble into the fuel rail, which would cause a huge decrease in fuel pressure to the front cylinder's injector. Since the air seeks out the highest part in the system, it would become "lodged" in the uppermost part of the fuel rail, where the air bleed screw is. (it's right under the Kohler CH26 panel above the flywheel). I had my pump sitting low, behind the engine on the frame under this scenario.

I resolved the issue by relocating the pump up by the fuel tank, right under the dash. It's still gravity feed to the pump, and although I can't explain exactly why it worked, it didd. Double check to see if you're getting air in the system as a start. The air bleed screw under the panel is a good first check. You can bleed the air off as it's running, but you'll undoubtedly get a little gas shooting out under pressure (insert standard health and safety language here....) When it's running under the conditions you describe, bleed the air off and see if it tends to even out after a while. Sometimes, the air works itself out of the sytem, but after sitting for a while, pressure in the sytem drops to ambient and you start from ground zero. It may be at start up/ warm up that some air is in the system. The EFI system in these engines works amazingly well, and I wouldn't change mine for a carburetor in my Chief.

Good luck! Let us know how you make out.
~m

[jdl]

Thank you both for your helpful advice. I'll be up there this weekend and will test this out and let you know how it works out! Thanks guys