Honda UMK435 Questions & Answers

From memory (been a while), there's a hole you stick a screwdriver or Allen key in to hold the shaft while you unscrew the head. It's usually buried and hidden in grass so you may need to clean things a bit to find it. :-)

Trimming head speed too slow, causing clutch slippage

Read the manual. If very dusty or you encounter lots of debri clean it more often

Hi. To my knowledge the bearing and spindle head unit are factory greased and sealed.
My 35 has been used on my small acreage every weekend and for many years.
The head unit still spins smoothly and has no shaft play.
I would think I will wear the motor out first.
I am sure your Honda dealer could effect repairs when and if needed.
For me I will just park it up and buy another Honda.
They are so reliable.

Place the holder in a vice and undo the cutting head, or use a pipe wrench on the holder to hold it firm. Remember it is a left hand thread.

Thanks but we have since sorted out the problem.

Open once you have got it started from cold.

Depends how hard you are working it. You should get an hour or so out of a tank.

Air filter, buy a new one off fee bay $4

Try putting compressed air through the fuel tank filter.

Sounds like the vent valve on the fuel filler cap is blocked.
Try starting it with the cap loose. If it runs smoothly you would need to air dust the cap or wash it in some petrol.
Cheers.

If you have a local Honda dealer go there. About $6 last time I got one.

I believe your motor might be cooked beyond repair. Most likely a lack of oil, or dirty oil. More expensive to fix a seized motor than to buy a new one. Sorry.

G'day Fraser, there could be any number of reasons for the engine losing power and stopping, but I always check the easiest (and cheapest) solutions first. In this case they would be the air cleaner and the fuel strainer, both of which you can service yourself (instructions are in the manual).

By the way, my wife complained of something similar one day, it turned out she had just left the choke on. I still give her a hard time about that.

I have had the same problem with my Honda brush cutter. Did all the maintenance jobs in the manual but although improved it never fixed it. It is always worse when cutting long or thick grass. It always seemed like it wasn't getting enough air but changing the air filter did not fix it. Loosening off the petrol cap fixed the problem but the cap then fell off with vibration. Yesterday I drilled a hole in the centre of the petrol cap and it has never worked better. I can rev it up as much as I like and it never cuts out. However not really knowing much about engines I wanted to ask if the air was being limited for a reason. What I have done now means that I can cut flat out but will it damage my engine?

Hi Annie. Had the same issue. That fuel cap is supposed to be vented but the tiny hole blocks up. The engine can't keep sucking fuel (especially when working hard) if there is a vacuum developing in the tank. So yes, you're on the right track. No issue with drilling a hole unless it is so big that junk gets in the fuel.

The thickness of the line doesn't matter. The length of the line is limited to how much you can loosely roll on - I get about 2.8 metres on each time.

You can use up to 3mm. I use it all the the time. It lasts longer than the thin line. I assume that because you have that model you would be cutting more than grass at times, so use the 2.7/2.8 mm or 3mm and you should be fine

I had a quick look through the product manual that came with my trimmer(UMK435) and couldn't find any specification for the thickness of line. That said when I purchased my trimmer I asked about the line thickness and ended up getting a spool of Honda brand line 0.27cm (2.7mm) in thickness This is really good stuff it has a squarish profile with edges on each lobe and cuts really well. I would normally use diamond line orange 0.27(2.7mm) on my sthill and was planning to use it on the Honda but I will probably stick with the Honda stuff there would seem to be very little difference between the 2 in my opinion.The Honda line is white in colour and the diameter is marked on the packaging as 0.27 (2.7mm) line. I can t actually tell you if I got more line on the spool that I would have if using the diamond line I didn't measure it (or have tried it yet on the Honda)The profile shape will actually assist in determining the actual amount of line you can spool but I don't think there would be much difference between these brands when it comes to it. It would only be centimetres if it was different The Honda line is dearer compared to diamond line but the pricing would be under $5.00 per spool in difference. Where you buy it from will also determine price etc. The original line supplied with the Honda( on the cutting head) when I got it was round and thicker and very soft (also white). It was ok but it didn't last too long I remember having the same experience with the original line that came on the sthill when I bought it back in 1995. I use my trimmer in a variety situations e.g. trimming concrete edges, retaining walls, heavy grass, some undergrowth, around poles etc. This diameter of line is a good all-round, from experience though If I were going to do a lot of clearing I would go up to 3mm line Hope this helps.

Buy youself a can of carby cleaner. Thoroughly go through the carby, replace or at least clean the filter in the pickup and run new premium fuel only. I recently got some awful E10 fuel and it ruined my stihl brushcutter, a mates minibike and very curiously seemed to 'melt' the tanks of 2 brand new Chinese pitbikes I had bought for my kids xmas presents. God knows what was in it but I had to do all of the above things to get them running again. They had exact same symptoms you speak of. I gave up on the stihl brushcutter in the end and bought the UMK435 and 8 hours use later am still trouble free.

The previous answer sounds pretty good. Only a theoretical possibility, I haven't tried it yet, but reduce its maximum speed; mine cuts out too on high speed. Let us know if any of the offered solutions work. Cheers

Ok, I see lots of people are having this bogging down problem with their Honda brushcutters. I had this problem too, got on YouTube and learned how to do a rebuild of the carby with a rebuild kit I bought at the dealer. It's not terribly hard (nor expensive, genuine kit was $40ish) but I have since found I can fix the problem by adding a splash of carby cleaner to the fuel and just leave it to idle while I make a coffee or bite to eat, come back and get to work again. The product I use is LiquiMoly Carb and Valve Cleaner or similar sounding name $15-20 but you don't use much - there are a few products that are similar, I can only vouch for this as I haven't tried any others, I have been doing this for about 5/6 years as needed, prob once a year or so. Btw, the problem generally comes from stale or bad fuel- yes, I get lazy sometimes and use old fuel when I shouldn't. Use fresh premium (under one month old) or put stabiliser in when you get it home to keep fuel longer term, DONT use E10 and it's best to tip unused fuel out of the machine when you are finished work (but I don't :-) except before I hang it up for the winter). My model is um?425 straight shaft so a bit smaller and with D handle but it's done a LOT of work, had it 10-12 years and still going hard, starts on 3rd pull now when cold, 1st pull once warm. Only looked at these reviews cause a 2nd hand 435 is available nearby and wanted to see if others are happy with the bigger model. Btw if you're having trouble with bump and feed, the line will bind (melts and sticks together inside the reel then won't feed) and then break off if it's under high load for too long like when cutting long grass where the ends of the line aren't wearing away. If your line is breaking off at the head and you keep having to pull head off to fix, just bump more often and rev up to let the cutter under the guard cut the ends off. I use 2.7mm cord, 3mm cost same for less length, I'd rather feed more often - 3mm will bind before it needs feeding but might be better for higher wear situations like constant edging or digging away dirt under fences. I prefer Honda star cord looks like a plus symbol in cross section - cuts grass better than round cord, but Husky cord is what my LD has, it's good enough and cheaper. Hope that helps, YMMV.

The switch certainly SHOULD shut it down, so it sounds like you have a dodgy switch - pretty ordinary after only 15 hrs use. Haven't had that problem myself, but I can't imagine it would cost much to replace. Good luck.

G'day mate GX35 Intake 0.08 +/- 0.02mm exhaust 0.11 +/- 0.02mm

Thanks heaps mate much appreciated!!

Not a problem mate glade to be of assistance