I have a black Horner twin (must be a 3.8), dual carb, CH Ignition, that has been a bear from day one. It's always been hard to start but once started runs fine. Engine has less than 10 hours run time on it. Took it out today and once again worked for an hour to get it to start and it would run the prime out but would not draw fuel on it's own, had a bubble in the line by the carb nipples and could see that fuel wasn't moving. Took the Walbro's apart and they are pristine inside, diaphrams are in good shape and all the jets are clean. Ignition battery shows 5.7 volts. When this engine runs it's a great engine but I can't for the life of me figure out why it's soooooo stinkin hard to start.
Is there a single carb conversion for this engine?

TIA,

It can be done..I have done 4 or 5 using a Walbrs SDC80 carb and reeds from a Homelite chain saw..
the problem with the twin carbs is nylon blocks underneath.Nylon is not strong enough to use for a carb insulator block..It strips easily and the pulse passages are too close to the threads and always leak..Blocks are made from G10 epoxy board won't strip.
Block off the pulse holes in the cylinders and put pressure fittings into the case..Tap the back plates of the carbs and put pressure fittings in there also..When you make the new blocks you can turn the carbs to get a better angle on the linkage..I like to make the shafts parallel and use DuBro ball fittings to connect them together..Way cheaper than a single carb conversion..
The Horner twin is almost as strong as a G62, and no vibration...

Oh, ok, that's pretty simple. I can get some 1/2 inch G10 and make some new blocks and it'll be real easy if I don't have to match the pulse pressure holes.
By "tap the backplate of the carb", you mean the plate that covers the diaphram, Right? And I assume it doesn't matter where on the case you tap as long as it's somewhere in the center chamber that gets pressure changes.

Thanks sooooo much, I know this can be a great engine if I can just get the bugs worked out.

Thanks again

The plate held on by one screw is the one to tap..There is a boss on the plate that has a small depression..If you look at the base of the carb there is a small hole for the pulse, plug it with some epoxy to prevent any leak ..The case can be tapped between the carbs, toward the rear..
There are other materials that can be used.. Bakelite strips too easy,,I like G10 because it machines well and is easy to find in Phoenix...Mine is 3/8 thick and costs $22.00 a square foot, enough for many blocks. The bolcks are held on by 5mm flathead machine screws, then tapped for 10-32 allens to hold the carbs on...

My name is Ray Woodall I bought Mr Horner off the market about 15 years ago. I have converted about 300 of these engines. used reeds and dolmar heads. The CO was called Centermark. I have some parts to repair or convert the motor. I would like to buy the crank and crank case.
Contact me at [email protected]