I have seen several folks speak of upping the jetting on the 6.5 duraforce models to eliminate the surging. Is this applicable to the 4.5 gold series engine on my 10520?
I have seen several folks speak of upping the jetting on the 6.5 duraforce models to eliminate the surging. Is this applicable to the 4.5 gold series engine on my 10520?
No. the F series with the walbro carburetor is fine. if it is surging you need to dial it in with the altitude adjustment or it needs new crank seals or the crankcase itself need to be split apart cleaned and resealed. That particular model has the plastic float so it is not adjustable so i doubt that is the problem. It could be a dirty carb though and that is where i would start first. Hope this helps.
I believe the ONLY model that had a lean-jetting issue was the 6.5 hp Duraforce. If you have lean issues with other models (older than the 6.5 hp Duraforce) it is generally just a clogged and/or dirty carb.
Actually, the jetting seems fine. I got this mower from a guy who was going to toss it several years ago. It had this issue where it would cut out, or not start at all..... Being a gearhead, I knew it was the coil so I relieved him of the mower and put a new coil on. That mower was the first thing that got moved to my current house. I took it there before the papers were even signed, as I wanted the lawn to look nice when we bought it. I did end up pulling it down about 2 years ago, as the ubiquitous leaky seal reared its head. It also got all new bearings, rings, gaskets, and wheels. The carb works fine, so I never opened it up. The only thing I did not replace is the piston, and there is a little slap now. I need to get one before that one breaks. Anyway, I am rambling.
The only "issue" is probably just a governor one. Usually, when I pulll the throttle back, the engine RPM will remain constant, or slightly decrease. When cold, it seems to idle alright. Once I mow with it, it seems to stay at a higher idle RPM. It does NOT have an air leak. Maybe a sticky air vane? Who knows? Now I have seen the videos on YouTube of the re-jetted Duraforce sitting there putting at idle, and I want my 4.5 to do that. I am ruined. I'll be ordering jets for my newly-acquired DuraForce, so I thought I might just order a handfull. Now I need to find a variable speed DuraForce, as this single speed drive will quickly irritate me.
I can't think of a Lawnboy 2-cycle mower made in the 1990's or later that didn't have some sort of speed control...to choose your mowing speed. If you don't have a lever on your handlebar, you are missing something. All the "F" engine, "V" engine and DuraForce engines have throttle levers. All those engines use a throttle fan that can stick, as gunk builds up on top the carb. This might explain your one-speed issue.
