OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Hand and Power Tolls Power Tools Oleo Mac HT27

Having a look at a HT27 for a friend. It starts and runs well but it smokes I would say excessively. That is the reason they wanted it checked. I know nothing about these machines apart from what I have read on the net.

It starts like a dream. First pull believe it or not. I have had it for a few days and tried it a couple of times. Flick the choke and it just fires and runs then blip the throttle and the choke comes off and it idles nicely. It runs a Walbro carby which has no adjustment apart from idle speed.

From what I have read they are classed a semi/commercial machine. I tipped out the existing petrol and run my 50:1 mix. No difference to the smoke. I checked the air cleaner and today I removed the exhaust looking for any build up. The port was very clean and the piston and cylinder that are visible look good. It only has one ring which contrasts what I have read about them.

Tomorrow I will try a compression test.

What are your thoughts?

The barrel does come off separately so I was thinking of trying a new ring to see what happens.

I threw a gauge on it and on a cold engine it ran up to 92psi after a few pulls.

Aldo, you didn't tell us whether it has always smoked or this has just come on it recently. If it has happened after it was no longer new, has the carburetor been tinkered with?

If it has no damage to the piston, and 92 psi compression, it sounds as if the problem is probably not piston ring leakage. Also, if the exhaust port is clean, it is not all that likely the muffler is carboned up (though not impossible). Personally I'd begin by looking for a dirty intake air filter, or a flooding carburetor. Rich mixture sounds a fairly likely cause of the problem, given that it starts from cold without using the primer, which its manufacturer doesn't seem to think it will do.

You might consider beginning by taking off the air filter, checking that the choke is opening fully, and running it briefly without the filter to see if it still smokes. If it does, the next most likely problem seems to be metering lever set too high (the leading cause of flooding or very rich mixture in diaphragm carburetors).

Hi Grumpy, I don't know the history on this machine except that it was recently purchased second hand.

On disassembly is appears to not have been apart before. I can't seem to find any info on it but it has a felt air cleaner that seemed to be oiled perhaps a tad excessively as it was all over the carb. I'm not sure if they are meant to be oiled but I pulled the carb down and rinsed all the oil residue off and also washed out the filter and I reinstalled it dry just till I run it for the first time which I didn't get a chance to do today.

I have nothing to check the metering level except to say that it is level across with a straight edge.

The plug was really carboned up flush to the top of the insulator cavity. I have cleaned everything up and will hopefully run it tomorrow arvy and see what happens.

Whether the air cleaner was supposed to be oil most likely depends on how dense and thick the felt is. Normally oiled filters are wrung out to ensure they only have an oil film, not a soggy mess, and wringing out felt without tearing it apart sounds difficult. If the oil was being sucked from the filter into the carburetor it sounds as if there may have been rather substantial suction going on. In other words, I suspect that filter should have been relatively dry, and that is likely to be the problem. Here is what the owner manual says:

AIR FILTER
- Every 8-10 working hours, take off the cover (A, Fig. 23) and the filter (B). The filter (B) should be cleaned by shaking it well and with a soft brush.

I can't make any sense out of that instruction if the filter is supposed to be oiled.

You probably know that trimmer is actually an Efco, made in Italy. It seems like a decent piece of equipment on a quick look. Here is the owner manual:

http://www.efcopower.com/sites/default/files/Efco_HT27.pdf

Hi guys, I had to change all the air filters on Honda's last Monday, that included 2 mowers, blower, strimmer and hedge trimmer.....all filters were genuine Honda spare parts, and all came pre-oiled in a sealed packet.

Most of the foam filters I have come across recommend as you have said grumpy, clean with a non flammable solvent or warm soapy water, let dry completely and then re-oil and wring out carefully leaving only a film of oil behind.

The filter on this machine must be very fine sponge to be able to run dry and still do its job of keeping the dust out.

Aldo said the filter is felt, Deejay. Felt tends to be rather dense. I have trouble imagining getting air through felt that was soaked in oil and dripping. My preferred theory is that the oil was a tenant's improvement, at least in quantity, but probably in being there at all. There is a picture of the felt in the owner manual, but I can't seem to post pictures in this forum. I agree that Honda foam pre-filters need to be oiled to be effective. The ones I have are only a few millimetres thick, and quite open. They wouldn't do much at all without oil. With oil, they keep the oiled paper secondary filters remarkably clean. Incidentally the foam filter on one of my Hondas was dry when I bought the mower, and I've seen instructions somewhere telling people to use them that way.

I ran the hedger today for 30 minutes work and it ran with far less smoke. I reinstalled the air cleaner without oil thinking the dense felt should do a decent job. Hedging isn't a dusty job compared to mowing and brushcutting/snipping etc. I'm pretty happy with the result.

I will replace the plug when I get a chance due to how much carbon was packed inside it. Replacing the fuel line with Tygon?? green coloured fuel line stopped and fuel leak around its entry point into the tank. It had no grommet, just a hole straight into the base of the fuel tank and some old stiff line made a decent fuel leak point.

Thanks for the help in sorting it.

I looked at a picture of the felt filter in the manual, Aldo, and I can't believe it is meant to have oil on it. Now that you have it clean and dry, if you replace the spark plug as well, by the time it runs long enough and hard enough to burn the carbon out of the muffler, it should be as clean-running as a new one. Thanks for reporting the outcome - I'll close this thread. If anyone needs to post to it, just PM a moderator.