A mate has what I think is a Zenoah 26 (or a look alike) that has a Zama Carb fitted. The carb reed block bolts to the head first using flush head screws and the carb then bolts to the reed block. The pulse hole exits from the side of the reed block to the carb by way of a fuel type tube. We are having heaps of problems getting the engine to idle properly and think the zama is the problem. We were given a Walbro carb to try but the reed block for the zama is completely different. I can work the head and tap some holes to get the walbro carb to fit and the pulse holes to line up - but my biggest concern is I don’t have a block to mount between the engine and carb. Is a reed block necessary or can I just mount the walbro directly to the head with the same results? I'm calling it a reed block - but its really just a huge spacer or insulator like this:
http://www.himodel.com/engines/Carbu...ol_Engine.html
Thanks for the help.

Hello You could mount the carb directly to the intake port, however, hot restarts may be a problem as the fuel is boiled off when the engine cools down. the block you are refering to is a spacer, not a reed block. My advice to you is to keep the spacer, as it insulates the 275-320 degree cylinder heat from the carb. Good luck

Why not first try rebuilding the Zama carb? If it works well at other speeds it's likely only a simple to fix problem inside the carb. Try the easy before jumping into the hard.

It's not a reed block, there are no reeds

If you make a new 'manifold' it can be easily done with a bit of aluminium plate. Fit thick gaskets either side to stop the heat transferring to the carb. Tufnol or fibre reinforced PTFE are alternative materials, but aluminium with gaskets is fine.


Is it the horrible Zama with only 1 needle?

"Is it the horrible Zama carb with only 1 needle?"

No - It the horrible one with 2 needles - H and L. The engines starts O/K (magneto - not CDI) with a finger over the velocity stack to prime and pop then a good run with an electric starter, but it only has one speed - full steam ahead. Adjusting the low end does nothing. We have had all the "experts" milling around offering advice and the general consensis is - change the carb. It seems by everybodys advice and experience that the Zama tends to be probmatic - if it goes, great - if it doesnt, replace. I'm reluctant to have money / time spent on it when after it's all added up a new CDI engine may be cheaper. I don't have the walbro spacer - just the carb that was given to us as a freeby to try - hense my reason to just bolt on the walbro direct to the head.

Horrible 2 needles: LOL

Make sure the butterfly is on the proper side of the throat. There are 3 holes on the cylinder side of the carb. Make sure when the butterfly is closed, it will cover all but one hole.