GardenKit

Paul, I would have a look at the fuel pickup hose in the first instance, failing that the carb may need an ultrasonic clean and a refurb with new membranes and diaphragms as it sounds like it may be using up the choke fuel and is then unable to pull fuel through the main jet. I had one a few weeks ago that I had the carb apart 3 times before getting it right. Good luck

Bury, a carb cleaning kit is available from Honda under part number 07JPZ-001-0003, priced at a whopping £32.90 plus vat. I have a little box with various diameter picks made from the straight bits of tension springs such as governor springs. It works. But this question has prompted me to order the Honda kit, which I have just done. As per Ultrasonic fluid, I use a brand name one from Ultrawave. You need a solution that is PH weak so as not to etch the aluminium. Hard metals use a high PH one. You can make your own, search google for recipies as I dont feel qualified to advise. Hope this helps.

If its a 6.5hp then I expect its a GX engine. If its hunting then its running a little weak, most likely due to a dirty jet and/or emulsification tube. The tiny holes get blocked with dirt or stale fuel 'varnish' and restrict the fuel flow. These can be cleaned with carb cleaner, airline and jet cleaner picks. This may cure the problem, but it could also be due to the same materials blocking, or restricting, the internal drillings in the carb body. These may clean by ultrasonic cleaning, but sometimes it just does not work and a new carb is needed. Genuine carbs are not cheap, but some pattern part carbs are available.

I know what you mean Rich. I get more trouble with Honda carbs than any other, and they are the very worse to get off, especially on the GCV engines. Getting them back on is a right fiddle, but the use of two steel guide bars makes it much simpler. Next time I do one I will take some pics and post, they may help someone. I had a Honda carb on and off 3 times today for cleaning after stale fuel, but could not get it to stop hunting, whacked a new carb on in the end, perfect. On to next job, 17" cylinder mower for full service and regrind.

Two more examples of stale fuel today. One was another Briggs pulsa jet carb. As soon as I took the fuel cap off I could smell the rank petrol. Cleaned the carb and fitted a new diaphragm kit (primer bulb was OK this time as the petrol was not quite as old as the OP) The thing just would not run properly, so I fitted a new carb as they are only about £20. Started it and it ran like a dream. The other was a Hayter with a Honda GCV engine. These things really hate stale or dirty fuel, I have more trouble with them than any other engine. Once again, an horrible smell of stale fuel and the engine was spluttering away like mad. On removal of the bowl I found the normal stale fuel 'varnish' around the bowl. A clean with carb cleaner and airline did no good, so the carb came off again for 40 minutes in the ultrasonic cleaner, its still buzzing away in there now. Hopefully it will be OK when I put it back on.

There is a 'need' for Aspen, just ask the regular users if they want to go back to unleaded! There is an ever increasing awareness of Aspen amongst users, and dealers. i think you will see many more dealers taking it on in the not too distant future.

Treequip, sorry if you misunderstood me. What I was trying to say is that pump prices change frequently, sometimes almost weekly, by 1 or 2 p. Aspen remains at the same RRP for some time, it certainly has not changed since I have been selling it, so when there is a price increase it is obviously larger than 1 or 2p, thereby catching up with the increases of pump fuel. I did not hint that it ever trailed unleaded, we all know it never has and never will. I only sell it, so am not responsible for setting the price.

Some dealers wont stock it because they dont understand it, or the need for it, and that they want to know there is a market for it before they commit. I understood it, stocked it, and found a market for it. Have just taken my 8th pallett load since September. I have no problem selling it despite its price. Let your local dealer know you want it.

The UK increase is applied by the UK supplier. I believe this is for the same reasons as the ever increasing petrol and diesel costs. Pump prices vary from day to day, slowly moving upwards, whilst a product like Aspen stays at the same RRP for some time and then increases in a larger bump to catch up. I cant see the price coming down, at least, not until the volume of sales increase dramatically. The sales nationwide are definately on the up though. If you want to use it dont wait for it to come down, bite the bullet and go for it.

I really dont know if an official test has been done, but dont think there is a lot of point. In the same way we dont need a test to prove that milk goes off, we dont need to prove that petrol goes off. Any small engine mechanic will see stale fuel of some degree on a daily basis. How long it takes to go off is dependant on factors such as temperature, light and humidity, in most ways just like milk but over a longer timeline. Because of the 'unstable' chemical make up of petrol, it starts its degradation from the day you buy it, starting its downhill slide. Most of the machines I service at this time of year will have 6 month old petrol in, and without doubt, are more difficult to start (if they start at all) and run poorly compared with fresh fuel. For that reason, every machine I service or repair has its fuel drained and replaced with fresh. This has a large financial impact on my business but is IMO essential. This season I have changed to filling every machine with Aspen rather than conditioned fuel and the feedback so far from customers is very positive.

All very interesting, but quite frankly useless information to the OP who merely wants to clean and re kit his carb. This will probably scare him off even trying. After all, although these jets are technically serviceable items, in the real, commercial world if they give trouble you simply change the carb. Looks to me like a point scoring exercise.

Briggs have been producing these things for years and they are impervious to petrol, that is, to fresh petrol. It has to be undestood that petrol is chemically 'unstable', it undergoes chemical reactions within itself which change its chemical makeup as time goes by. It loses its original properties of combustion, volatility,octane rating etc as it ages and takes on an acidic nature which will attack materials that fresh petrol will not. Pump petrol was never formulated to last, there is no need for it last normally. You buy it for your car today and its gone by next week. In our industry, as well as the marine market this stuff sits around and changes into a useless gunk which causes costly repair. Fresh fuel is no problem at all, but dont let it age.

I,m pleased you got it sorted Ben.

No, this is definately due to stale fuel, its something we see quite often in the trade, usually in machines which have not been used for some time. The stale petrol will be very dark in colour and have a very unpleasant smell, it will also be quite viscous. As I said earlier, I would expect this petrol to be 12-18 months old, so when the customer came in today to collect the mower I asked her how long since she had used it, and she said she had been using it OK all last year. I suggested she use Aspen, and during the course of the sales pitch to justify the extra cost, it turned out that a 5 litre can would last her about 2 years as she only has a very small lawn. Judging by that she would have bought that petrol in 2010, so little wonder she had problems. As regards the oil separation of 2T mix, believe me, it does happen, this is why all operator books will tell you not to use a mix after 30days.

CO levels from Aspen are 20% lower than from pump fuels. Aspen v Premium Unleaded - clean fuels,environmental and green fuels, petrol and bio diesel in the uk

Sorry, bad news. Just had an email to say that the price of Aspen will be rising to £18.15 for 5litres of 2T effective 1st April. (from £17.60 currently) inc vat So get your orders into to your supplier now to beat the increase.

Jamie, you obviously have a good fuel management regime. e.g knowing that your fuel is getting older and using it up in the mower. Keep it up and you wont have problems with pump fuel. The shelf life of pump petrol is generally taken to be 30 days. In truth it is degrading from the moment it is purchased, the rate of degradation depends on storage conditions such as heat and damp. Some carburation systems are more tolerant of stale fuel than others, the older carbs in particular are less fussy. Generally petrol of 6 months old does not cause too many noticeable problems, but without doubt the power produced will be less. and of course with 2t there is the risk of oil seperation. Starting will doubtless be a little more difficult and the exhaust fumes will be heavier. In the repair trade however, it is very common to have machines in with stale fuel problems of varying degree. It is a very real problem which everyone needs to be aware of, hence the post. The example pictured is extreme and the photos dont show the full effect. The rubber is slimy as though its melting, the melted rubber has gone into the carb passages, and the stink of stale petrol is nauseating and difficult to wash away. I dont know how old this petrol was but would guess at 12 to 18 months from past experience.

And I remember our PM of a few weeks ago Spud, I recon that was an example?

But probably best if non-technicians leave these things well alone and stick to a simple clean and fit a new diaphragm kit. Can't go too far wrong and it normally sorts it out.

I know there are a few members who have never experienced the damage done by stale petrol so thought this might be of interest I replaced this carb primer on a Briggs and Stratton pulsa jet carb today. The pictures show a partially dissolved and swollen primer bulb alongside a new one, and the sticky mess of dissolved rubber left in the carb. All primers, hoses and diaphragms will be attacked by stale petrol so best to keep it fresh, or use Aspen.

The problem with getting a refund or a replacement machine is that there are 3 parties involved, the purchaser the dealer the manufacturer Your contract is with the dealer, but he did not make the machine, so is not responsible for its faults, but it is his problem to put it right. It is only fair to let him try to correct the issue in the first place. He will be paid for his trouble under the warranty system, but it is unlikely that he will be supported by the manufacturer if he refunds or exchanges the machine. They will expect him to repair it, and it will be his problem to resell it. In any case I think it is doubtfull that after nearly 12 months a refund will be considered unless the dealer has a very strong business relationship with the purchaser and refunds, or exchanges due to goodwill. If he is unwilling to exchange or refund on his own back, then he will have to discuss the particular issue with the manufacturer, who may, in the first instance want the machine back to their own workshops for inspection, so be prepared for a little downtime. These are of course, generalisations, and there are always exceptions. Good luck.

Firstly Blower/Vacs As on the previous thread, avoid the cheapo makes sold online or in shed stores, instead go for one from your local machinery repair and sales shop. He will likely have a small choice of economy and premium models to suit your budget, but unlike the online ones, these should be fully supported with warranty and spares from the dealer.They will all have similar performance. I use the Mitox as my economy model and Tanaka as premium. The tanaka cost twice as much as the Mitox and does have a better feel to it. Many folk think that a vac conversion will be handy, but after using it once its left in the shed, frankly none work well and are very slow to use. Best stick to a blower IMO. Secondly, you have not got a B&S lawnmower, you have a mower with a B&S engine on it. If you identify it accurately we will be able to advise on a suitable machine that is lighter and smaller. Many of my gardening contractors use the ALKO 4610HPD steel deck, 46 cm, self propelled mower with a Honda engine. They are priced slightly over £400 and offer excellent value. They are very reasonable quality and not over heavy.

Its likely to be too little fuel, or too much air. I had a Dolmar PS34 yesterday with exactly the same symptons. A good carb overhaul sorted that one out. It had not been used for a while and the solids from stale fuel had choked the carb.

I,ve had several bring fake Stihls to me for warranty repair, its difficult to know how to break the news to them without making them feel a bit stupid. There was one I did not feel sorry for though, as he had taken great pleasure a few weeks earlier, telling me I was way too expensive on my quote for his new saw. Said he could get it several hundred pounds cheaper on the internet!:lol:

You dont say where you are, but I guess not the UK as the MS311 is not a UK model as far as I can see.