Great Dane Surfer losing power


LawnSite Member
Olive Branch, MS
2000 Great Dane 52" Surfer, 815 hrs, 18hp Kohler

Yesterday I used my Surfer for the 2nd time this year. Before the 1st time, I removed and sharpened the blades, checked the oil, and tightened the main drive belt. It cut fine.

This time when I got on it I noticed that as I would get the mower off of level from side to side or go up a slight slope it would lose power which at first I thought was like it was starving for fuel. Then, I noticed that as I did a 180 to cut another pass next to where I had just come it did the same thing, the engine RPMs would drop real low and the hydraulics would get real mushy. If I stopped and gave it a few seconds it would rev back up and I could cut again. The problem seemed to get worse the longer I worked. I finally stopped and checked things out again and the oil level was good and plenty of gas, but I noticed the main drive belt was very loose again. I've never had a problem with that belt loosening up on its own before so I was surprised. I tightened it back up and felt that I had finally found the problem. But, I hadn't. As I got back to cutting, it still would lose power as it would go either down a hill or up one. When I disengaged the blades it ran fine.

The only things I could think that it might be would be:
1. Dirt in the carburetor
2. Dirt in the fuel filter
3. Dirty air filter
Does any of those sound possible? What else might it be?

Thanks guys,



LawnSite Member
Olive Branch, MS
Do a compression test. Your local automotive store should rent you a gauge if you don't have one for free.
I was afraid somebody was going to suggest that. I had thought of it last night but forgot to list it.

I did not drain the gas but I put a good amount of SeaFoam in the mostly empty tank. Then I shut off the fuel line and ran the gas out of the carb.

I'll check the fuel filter. I put a new glass inline one on last year.