Engine struggles above idle speed

[cdrnet]

Hi everyone, I wonder if anyone can help with my Walker MBK-23 Kholer EFI mower.

All was fine until I had to replace the fuel line. I manually primed it by squirting fuel into the pipe from both ends and also filled the line down to the engine before reconnecting.

She took a while to fire up with coughing and spluttering until I relaised that the problem was the throttle position.

She runs just fine on idle however when I attempt to increase the engine speed, it just won't take it and coughs and splutters; seemingly starved of fuel. I have ruled out the air filter being the problem and having checked all connections, I am not completely stuck.

Any guidance will be gratefully received.

Thanks,
Andrew

 

[bertsmobile1]

Why did you have to replace the fuel line ?
Could be a lump of the old one stuck some where .
The usual place is in front ( fuel line side ) of the needle valve in the carb .
You need to confirm that you have a good strong fuel flow at the carb by removing the fuel line & cranking the engine .

 

[cdrnet]

Thanks for the reply. I had to replace the fuel line because someone tried to steal fuel from the mower and ripped it out.

I'd be OK with a carb, but this one is EFI. It's like with diesel motors that won't get above idling without first priming the fuel pump. I don't believe I can prime an EFI system?

I can hear the fuel pump cycle, so that seems OK. I guess I should start with checking there's no debris in the fuel line and go from there. Mower runs perfectly, but without any power.

If I keep her going for too long, she seems to overheat and spoke pumps out of the exhaust which is when I power off.

 

[ILENGINE]

Can you supply us with the actual Kohler model number so we can see exactly which EFI system that you have. There have been several changes over the years.

 

[cdrnet]

Thanks for the reply. Here's a photo:

 

[ILENGINE]

The problem may be unrelated to the fuel line issue, I have a concern that the fuel line issues may of introduced dirt into the non serviceable fuel filter inside of the fuel pump module. Are all the correct fuel filters in place or were they replace with just a generic fuel filter. The fuel filter between the lift pump and the fuel pump module is very important to protect the high pressure pump.

Is the MIL light coming on or blicking.

 

[cdrnet]

WOW - You seem to have uncovered the entire story by referring to the bits I felt unnecessary to disclose.

So this is the full story: Whilst attempting to steal fuel, the hose securing nipple snapped off the connecting fuel filter, as per the attached picture. Our gardener installed a generic one he found on eBay that looked the same. When the mower failed to start, he put it in the too hard basket and passed it to me saying "you're mower needs fixing".

I poured some fuel into the line that goes to the engine and she fired up and ran at full revs, so I was happy it could be fixed. I then noticed that the 'fuel in', 'waste fuel out' lines were on the wrong connectors, so I swapped them and started her up.

This is where I am now with an idle only engine. I suspect that it might well be screwed, as when I put fuel into the line heading to the engine, she doesn't rev up.

I guess it is too late to get the right filter and we need a new fuel pump also?

Thank you so much for this specialist information which is very much appreciated.

The problem may be unrelated to the fuel line issue, I have a concern that the fuel line issues may of introduced dirt into the non serviceable fuel filter inside of the fuel pump module. Are all the correct fuel filters in place or were they replace with just a generic fuel filter. The fuel filter between the lift pump and the fuel pump module is very important to protect the high pressure pump.

Is the MIL light coming on or blicking.

 

[ILENGINE]

The fuel filter that is suppose to be between the vacuum/mechanical pump and the high pressure injection pump needs to be the 2 micron filter to protect the pump and preventing the internal 10 micron filter from clogging. The filter between the tank and the low pressure pump can be a 50-75 micron filter.

 

[cdrnet]

Thank you. Fortunately I found a photo of the old / broken fuel filter and realised that the new one had been installed upside down. I reinstalled it, as per the photo and she fired up with full revs and ran. I engaged the drive and it appeared to be running at full power. I engaged the blades and did about 5 minutes of cutting before the engine spluttered a few times and puffed white smoke out of the back. This cleared after a few seconds and we were back to full power. When it did the same again, I disengaged the blades and drive back under cover. The spluttering continued so I powered down. Is there a chance that this could be related to old fuel running low and it needing a refill of fresh fuel?

 

[ILENGINE]

Or picking up water out of the tank.