OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Trimmers and Brushcutters McCulloch Trimmers & Brushcutters McCulloch 2816 snipper

Let's go back to square 1: what makes you think this carburetor has a problem? What are you trying to fix?

Acquired second hand. Told the machine was difficult to start. Pulled down and cleaned piston, no spark, replaced plug which was completely fouled up, oil residue everywhere, still no spark, found replacement coil, now have spark. Pulled carby off to clean, as mentioned, oil dryed throughout carby, diaphragm needs replacement, maybe petrol plunger also. Decided to get repair carby kit. Have not yet received kit and after checking adjustment needles, concerned that the carby may be shot anyway. Best can hope for now is to install carby kit and see if it fires up. If it doesn't, guess it may be time to retire the lot?. Pedro

If there is a fair amount of soft black carbon in the combustion chamber and exhaust port, the previous tenant may have been using too much oil in the fuel, and/or letting the engine idle a lot. However before letting it go at that, I suggest that you check the compression with and without a small (tea)spoonful of oil put into the combustion chamber through the spark plug hole. If the compression increases substantially with the oil in place, chances are the piston rings are worn out or damaged. Also, take a look at the crankshaft seal to see if it is leaking (The 2816 appears to be a cantilevered crankshaft design, with only one seal).

If one or both of the diaphragms are stiff and/or have wear marks, the carburetor needs an overhaul kit. So far I see no reason to suspect a problem with the mixture needles, which really only happens if the previous tenant has played with them.

Essentially, most whipper snippers are disposed of because they have become difficult to start. Sometimes the reason is that the spark plug has deteriorated or dirty fuel has blocked a fuel filter (in tank or carburetor) or less often, a jet or passage. In the remaining cases, either an incompetent tenant has messed them up (and there are usually visible signs of this) or a possibly competent tenant knows very well that they are worn out. You go through a process to find out which of these three failure modes has occurred.