MDS 148 conversion
 

Has anyone tried converting the MDS 148 engine?
I have one, new in the box that I want to make the Walbro adapter for. Looks like it doesn't have rollers on the conrod lower end, but not a problem as I'll be doing the 20-1 mix for it anyway.
Any ideas for this engine greatly appreciated.

John

RE: MDS 148 conversion
 

MDS has a bit of a hit and miss history. When good, it's a powerful engine.
use 1 in 8 oil. 1 in 20 is cutting it thin.

RE: MDS 148 conversion
 

Wow, 8 to 1 ratio? That's gonna have a seriously tough time making it past the high and low needles on a Walbro carb. Probably have to open em to about what, maybe 5 turns out??
I've run a K&B .61 on 16-1 Belray oil. You sure?
Well, I'll try it. Guess I better buy stocks in NGK ME8 sparkplugs. LOL

John

RE: MDS 148 conversion
 

12.5% oil is not too much for a small plain bearing engine. 7% oil in small engines is quite common with needle bearings.
Most walbro carbs will manage this mix quite well. If not, slightly raise the fulcrum lever height.

RE: MDS 148 conversion
 

I was thinking about raising the lever about 10 thousandths or so just to be on the safe side. Last engine I ran alot of oil in was an ASP 108. It ran well on ignition and no bad habits except the usual touchy stock carb needle.
My K&B 61 with Perry carb also worked well until it's demise performing a spectacular figure 9. Oh well.

If I drill and tap the back cover on the MDS, what orifice size in the fitting, if it matters, do you recommend for the Walbro pump to operate correctly?

John

RE: MDS 148 conversion
 

The MVVS pulse fittings are M4 with a 2.2mm orifice. These fit all their engines.