OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Hand and Power Tolls Power Tools Shindaiwa HT-20 hedge trimmer

I was hoping somebody could help out with some info on the HT-20 single sided hedge trimmer by Shindaiwa?

I tried asking my local and they are very disinterested in even working out what years the unit was manufactured. I was also after what capacity the engine is? All they could tell me is that parts are discontinued.

I have tried Google and can't seem to find any useful info.

Here are some pictures of the model in question, they are from a sales ad.

I have had a good look at the machine today and came away with plenty of spark, clean air filter, excellent plug and plenty of compression.

I can't seem to work out a routine starting procedure. This is also the comment from the previous owner.

The machine has a small bulb in the fuel line just before the carby. Under the carb (where most modern machines have their primer bulb) this one has a lever with "press" stamped into it. Also on the throttle is a lock which keeps the throttle open. It also has a choke.

I can't fugure out why there is a primer bulb on the fuel line and a lever which I guess replaces the usual primer bulb. Surely these two items don't serve the same function.

When I squeeze the fuel primer bulb and it pressurizes the machine starts very cleanly and usually on the first pull. Occasionally the primer doesn't feel at though fuel passes and no amout of pulling will fire it up. Obviously there is little or no fuel in the system.

The fuel bulb pressurizes if I release the fuel cap.

The unit does not have a fuel return line via the primer. It simply drips out of an open ended line.

Edit. You can see the push tab on the primer lever in the last photo and the fuel line bulb in the third last shot under the four intake tubes on the airfilter housing.

Aldo, you are probably aware of this but a lot of chainsaws, trimmers etc. are prone to starting problems due to the system that allows air into the fuel tank, to replace the fuel pumped out, not working. You can diagnose the problem by checking whether it will start and continue to run when you loosen the cap, but not otherwise. Most models have either a squashed tube or a flap valve built into the petrol tank cap, to allow the air in. When the machine is left laying around for a long time the oil oxidises in this tank cap vent, and the oxidised oil glues the valve shut. If that happens you need to wash the vent in petrol to clean it, after which it will be as good as new.

Grumpy I have had a good look at the tank cap and it seems to have no vent. I will suss out the rest of the tank to see if there is a separate vent elsewhere. Once I had it running today it ran well for around 10 minutes. Hot starts are no issue either.

This is the carb.

The only ones I've seen with no vent in the tank cap, have a separate air line entering the tank output fitting where the fuel line exits. Sometimes the air line meanders around the engine then has an open end - the meandering seems to be designed to prevent fuel from escaping from that air line. Others have the air line connect to the carburetor so that any fuel that escapes from it ends up going into the air intake.

If you have no air line, and no vent in the tank cap, you may need to consider the possibility that you have the wrong tank cap.

This is a few pictures of the carb features I mentioned.

The primer bulb in the fuel line


The lever at the base of the carb the primes fuel through the amber hose in the bottom of the pic.


The fuel cap which appears to be similar to most Shindaiwa units and the one pictured in the first post which is identical to my machine.

Does it start and run properly if you leave the fuel tank cap loose?

I doubt that it had two primers when it was new. That raises the possibility that one of the primers is causing a problem to the venting arrangement.

Having said all that, some of those things have a remarkable collection of pipes running in all directions doing incomprehensible things. Are you confident that the fuel system has not been modified by the previous tenant?

I'm wondering if the HT20 is a hedgeclipper model of the T20 brushcutter. Just in case it is, here is the T20 workshop manual:
http://golftechs.us/Manuals/shin%20trimmers.pdf

I notice that the T20, and every other Shindaiwa brushcutter except one, has a duckbill fuel tank vent. I haven't heard that term before, but presumably it is the usual flattened tube vent that acts as a one-way valve, and is usually in the filler cap.

Basically I undo the cap, prime the black bulb till pressure is there then I pump the lever under the carb. Screw the fuel cap down and it starts second pull. It runs with no issues. I trimmed my hedges today and it ran perfectly.

As for tampered with, I think it's all original. The pictures of the HT-20 in my first post are from a unit for sale on Gumtree. It looks identical to mine with both a primer on the black fuel line and a lever under the carb. This also matches the diagram I pulled off the net.

A manual would be great but I cannot find one on the net.

Inside the carby air filter housing is that typical looking date code stamped on plastic parts of power equipment I have played with. Mine says 8th '93 so if that is to be believed, it is an old unit in good shape. Finding a manual or even just reference to the correct starting sequence would be difficult.

Thanks for finding that Grumpy, much appreciated.

It does seem to show that the setup I have is correct, specifically the bulb in the fuel line and the primer lever under the carb.

If you've got it consistently starting second pull and then running perfectly for as long as you use it, it sounds as if things are in good shape and it's just another case of a complicated fuel system on a small all-position engine. I'll leave this thread open for now, in case you have more to report later.