Amazed Posted April 13, 2014 Report Share Posted April 13, 2014 Hi all seems the best place to ask. I have petrol hedge trimmer and they seem to work fine but over heat after about 20 mins then will need a long time to cool. Any ideas on what could be causing this ? There not an expensive set but quite effective when running. They are sabre hts-43 Many thanks Karl. Quote Link to comment Share on other sites More sharing options...
scutt Posted April 13, 2014 Report Share Posted April 13, 2014 cooling fins blocked Quote Link to comment Share on other sites More sharing options...
Pigeon Paul Posted April 13, 2014 Report Share Posted April 13, 2014 As above or more likely too lean a petrol/oil mix. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 13, 2014 Report Share Posted April 13, 2014 (edited) Is it clean and free from obstructions around the cooling fins Are the vanes on the fly wheel all intact for blowing air over the fins, once again clean and uninstructed Is all the panel work correctly fitted to direct that blown air where it needs to be Have you mixed the oil / petrol correctly (to much oil will cause a lean mix which will run hot) How old is it, has it sat for a while, if so the carb diaphragm could be a touch stiff resulting in running weak Edited April 13, 2014 by Paul223 Quote Link to comment Share on other sites More sharing options...
Pigeon Paul Posted April 13, 2014 Report Share Posted April 13, 2014 Too little oil would be a lean mix and cause overheating. Too much oil would be a rich mix. Quote Link to comment Share on other sites More sharing options...
Amazed Posted April 13, 2014 Author Report Share Posted April 13, 2014 It's pretty clean inside but is sat for quite a while, it may be the mix as suggested what's the sugested ratio ? Thanks everyone Karl. Quote Link to comment Share on other sites More sharing options...
HDAV Posted April 13, 2014 Report Share Posted April 13, 2014 (edited) It's pretty clean inside but is sat for quite a while, it may be the mix as suggested what's the sugested ratio ? Thanks everyone Karl. Ratio is as per manufacturer........ somewhere between 25:1 and 100:1....... normally (check manual and side of machine) http://www.texas.dk/sparepart/usermanual/haekkeklippere/HTS43.pdf 32:1 which is an unusual mix 25:1 and 50:1 more common so your probably are running lean 50:1 mix? When you say its sat for a while have you pout fresh fuel in as old fuel can cause havoc These are really useful as you mix up 1l at a time and keep the petrol fresh in a separate can and reduce wastage. http://www.screwfix.com/p/hp-120-2-stroke-engine-oil-mixing-bottle-1ltr/46908?kpid=46908&cm_mmc=Google-_-Product%20Listing%20Ads-_-Sales%20Tracking-_-sales%20tracking%20url&gclid=CIrCgfiX3b0CFabLtAodUSIA5A Edited April 13, 2014 by HDAV Quote Link to comment Share on other sites More sharing options...
timps Posted April 13, 2014 Report Share Posted April 13, 2014 You have two fuel ratios in a two stroke, first one fuel/oil mix and second one air/fuel-oil mix. So by adding more oil and you will richen the fuel oil mix, however by adding more oil means less fuel in the same volume of premix which leans the the air fuel ratio so it runs lean on the same carburettor jets. A lean air fuel ratio can cause overheating just as too little oil can cause plug fouling due to an over rich air fuel mix. Most people get confused between the two ratios and go the wrong way on oil ratio to combat the problem. As far as the correct oil to fuel ratio you have to match the ratio to the jets in your carburettor. They will have jetted it so the air to fuel ratio is correct with a specific oil to fuel ratio so you need to get from the manufacturer what ratio it is jetted for. I could jet my carb on my 2 stroke race bikes to take a very wide range of fuel oil ratios but if I ran the wrong mix with the wrong jets I would be asking for trouble. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 13, 2014 Report Share Posted April 13, 2014 Too little oil would be a lean mix and cause overheating. Too much oil would be a rich mix.Adding to much oil in the hope it will provide more lubrication changes the mix to such an extent that it runs lean, by lean were talking air to petrol ratio, the oil has no biases on fuel air ratio as a burning factor A lean mix does two things in a two stroke ..... firstly it'll burn much hotter and faster, some times resulting in pinking, preignition which WILL result in a melted piston crown secondly the lean mix has less effect absorbing temperature from the 'squish' area between cylinder head and piston crown To much oil is as bad as not enough, use the correct mixture and use a quality oil Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 13, 2014 Report Share Posted April 13, 2014 You have two fuel ratios in a two stroke, first one fuel/oil mix and second one air/fuel-oil mix. So by adding more oil and you will richen the fuel oil mix, however by adding more oil means less fuel in the same volume of premix which leans the the air fuel ratio so it runs lean on the same carburettor jets. A lean air fuel ratio can cause overheating just as too little oil can cause plug fouling due to an over rich air fuel mix. Most people get confused between the two ratios and go the wrong way on oil ratio to combat the problem. As far as the correct oil to fuel ratio you have to match the ratio to the jets in your carburettor. They will have jetted it so the air to fuel ratio is correct with a specific oil to fuel ratio so you need to get from the manufacturer what ratio it is jetted for. I could jet my carb on my 2 stroke race bikes to take a very wide range of fuel oil ratios but if I ran the wrong mix with the wrong jets I would be asking for trouble. Timps was a bit quicker typing Quote Link to comment Share on other sites More sharing options...
timps Posted April 13, 2014 Report Share Posted April 13, 2014 Timps was a bit quicker typing Sorry The amount of times I had this discussion at the race track, usually with plug fouling and the insistence they need to 'lean' the mix by reducing the oil ratio. Quote Link to comment Share on other sites More sharing options...
timps Posted April 13, 2014 Report Share Posted April 13, 2014 Ratio is as per manufacturer........ somewhere between 25:1 and 100:1....... normally (check manual and side of machine) http://www.texas.dk/sparepart/usermanual/haekkeklippere/HTS43.pdf 32:1 which is an unusual mix 25:1 and 50:1 more common so your probably are running lean 50:1 mix? 32 to 1 is very common in the USA as 1 US gallon = 4 US ounces of oil and they like to keep it simple. The race lads over here used it a lot as there was a lot of data form the yanks on carburettor setup on a 32 to 1 mix so a lot of stuff is designed for 32 to 1 for the American market. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 13, 2014 Report Share Posted April 13, 2014 For 32:1 buy the stilh oil sachets (100ml) and mix with 3.2 ltr of fuel 32 to 1 is very common in the USA as 1 US gallon = 4 US ounces of oil and they like to keep it simple. The race lads over here used it a lot as there was a lot of data form the yanks on carburettor setup on a 32 to 1 mix so a lot of stuff is designed for 32 to 1 for the American market.Can't argue with that Quote Link to comment Share on other sites More sharing options...
HDAV Posted April 13, 2014 Report Share Posted April 13, 2014 32 to 1 is very common in the USA as 1 US gallon = 4 US ounces of oil and they like to keep it simple. The race lads over here used it a lot as there was a lot of data form the yanks on carburettor setup on a 32 to 1 mix so a lot of stuff is designed for 32 to 1 for the American market.I dud t know that I think my Stihl is 50:1 mariner outboard 100:1 Quote Link to comment Share on other sites More sharing options...
Amazed Posted April 13, 2014 Author Report Share Posted April 13, 2014 Thanks for the information chaps, it due to come from the shed. Not much of a Gardner I will drain what fuel is in and do a correct mix based on what you said. I have no instructions on the trimers they are American that's all I know. So the 32:1 seems fitting All the best Karl. Quote Link to comment Share on other sites More sharing options...
tiny tim Posted April 13, 2014 Report Share Posted April 13, 2014 i have seized a blown up many 2 strokes and the one bit of advice I can give is use high quality oil..the cheap 2 stroke from the garage will ruin machines Quote Link to comment Share on other sites More sharing options...
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