The only bit I don't necessarily agree with is suction due to turning the tap off causing the needle to stick worse - there is a hole in the primer that will let air pressure out.
The suction isn't on the float chamber side, it's on the fuel hose side.
This could happen either way but it's more likely if the fuel hose is empty.
Think of it like this... If the fuel hose is full of fuel because you stopped the mower, and then turned off the fuel tap, and then, after being stored for a week the fuel pressure changes because it's cold in the shed. The pressure and vacuum in the fuel hose will change a bit.
Then instead, imagine if that fuel line was empty and full of air, or partially full of air. It gets cold, the air molecules condense and the pressure lowers, creating vacuum or suction in the hose. It can't suck from the tap side, so it sucks from the needle side, then the rubber tip gets pulled into the seat in the primer cap and gets stuck.
Converse, I repaired a mates mower last year (talon) and he asked why it didn't smell as much during use. All I had done was drain the dirt out of the tank & carby and refill with fresh 98 octane. Maybe 91 has more sulphur in it and make it stink. Fuel and can was fine - it was the fuel line disintegrating inside that made it clog and surge.He said it returned to normal smell after he refilled.
That being said, when ever I really hammer the car (which I try to avoid but sometimes you can't), it stinks of rotten egg gas from the cat convertor, and thats on 98.
I am in the process of reading a rather interesting book on motor petroleum, and it does make mention of a quite concerning increase in octane requirement with even small amounts of carbon build up. Once I have a bit of a re-read, I will remember what the figure was. Its is a book made after tetra-ethyl lead, but before MTBE was banned
I am in the process of reading a rather interesting book on motor petroleum, and it does make mention of a quite concerning increase in octane requirement with even small amounts of carbon build up. Once I have a bit of a re-read, I will remember what the figure was. Its is a book made after tetra-ethyl lead, but before MTBE was banned
Hi Tyler, I can give you my story on this, when I first bought my old Ford XC Falcon with the 302 V8, there was still good old Leaded Super available and the engine loved that stuff. Anyway after a few years they started phasing out Leaded Super and were replacing it with that LRP "Lead Replacement Petrol". Anyway after a while I noticed my engine started to make a metallic tapping type noise under hard revs. I didn't really quite know what this noise was I was thinking maybe something was a bit loose and rattling around the engine. Anyway I took my mate for a drive who was more into working on engines and race cars at the time and asked him what he thought this noise was. He said it sounds like the engine is pinging. I was like gees it never used to do that before. Then it clicked, it was the new damn LRP "Lead Replacement Petrol". It must have had a lower octane than the old Leaded Super where my engine never pinged at all. I never knew what the sound of pinging was when the car was always run on Leaded Super. Anyway there is my experience in finding out all about how good the old Leaded petrol was for those classic engines. I think back then Leaded Super had an octane rating of 97 or 98? That new LRP rubbish was like running water compared to good old Super!
Yes these days if you want to try and put a stop to your older engine from pinging your best bet is to try running it on Premium 98. In most cases it will stop the engine pinging because of the higher octane like the old Leaded Super used to be. I have ran some older 4 cylinder cars from the early 80's on premium 98 and it has stopped the pinging completely. If I run these engine's on anything lower than 98 they will ping. It's probably also from years of carbon build up in the chambers. Well I know running 98 has stopped the pinging on older engines and you don't have to mess around with rebuilding the distributor or adjusting the timing.
Then there's the other thing about how the older engines hard softer exhaust valve seats and this is where the old leaded petrol used to coat things and look after them. Some older cars had hardened valve seats and can be safely run on unleaded where others need some sort of additive added to the fuel to try and save the valve seats.
Cheers!
Zip a dee doo dah, zip a dee ay, another trash picked Victa, hip hip Hooray!
That what I do Converse, the Camira now gets 98, with valve saver every other fill - it has an alloy head and supposedly doesn't need any valve saver. But Red and Blue Holden engines would, same as 302 Fords and probably any 3.3L or 4.1 straight 6 before the XD got the Honda designed alloy head.
I put the timing back a couple more degrees last month as it was pinging at bigger throttle openings (under 15 mm hg on the economy gauge - remember them?), and I think another tweak is in order next week when I do the 6 monthly oil change (only does 1100km between them).
Its funny in the off season we all end up talking about cars as much as mowers haha, but I'm not complaining
Except for that one time, I've always run my PTs on 91, but I add Sta-Bil. I read a tech paper from someone who'd know (it was either an engine manufacturer, or oil company, but I can't remember which!) and they recommended sticking with 91 RON. The only exception is for smaller, high performance two strokes that rev. I'll use MotoMix for those. I thought that was a great way to part with my money until I read the patent and tech papers on that.
Funny about the mention of sulphur content in fuels. I cannot stand the smell of burnt 91. I can pick who uses what fuel in their car, and it's not necessarily a gift...!
I do love the smell of AVGAS on a hot day...bring back the TEL.
I don't collect mowers. I just require Multiple Mowing Solutions™.
I can also sense which RON they put in Mystyler, especially the cars about 15-20 years old now that their flash lambda sensors aren't so precise with age and wear
I found where the book said about octane requirement increase (ORI). Just so I don't end up crowding Norm's Victa Needle thread too much with this good more car petrol related info, I will make a new thread and put the info in there
Hi Jeff, too much info happened here at the moment so I will address the 600 issue with you. I have 2 of them here and I am convinced these slashers are not suited to the PT's for some reason. I have fitted 4 motors to these and they do not work well. The motors run fine on a standard base. I'm at the point of contemplating fitting F/C's on them. The bloke who owns one of them was on about fitting a Suzuki on his but I had told him I thought they might be too small cc wise, he wasn't listening but I think I convinced him yesterday when I told him they were a Chinese copy. He is trying to find a Honda for it now. At least I have a drawing here somewhere of the adapter plate that I need to make to fit an F/C on the later base.
To be fair I have gone through over 100 of the viton tipped needles, some work fine and never have a problem, then some cause issues and when this happens I can go through as many as 4 primer caps and needles before I get a combination that works and that mower settles down.These issues always arise usually in the first week or so so I do not believe oil is the issue but it could be if the mower was left to sit for many months.
Hi Max, I will make up one of those needles and see if it works, there is another 5 PT's I put in the front garage that I haven't looked at yet. Probably a good starting point With the needles, even with the viton tipped ones I have had to shorten a few of them by about half a mm. This must be because the seat height (depth) must vary slightly in the primer cap. When the primer cap is fitted in the body, the float is unable to drop enough to allow the needle to drop away from the seat. This is also compounded by the fact the viton tip will swell a fraction after a day in the fuel and this combined with the limited float travel it can be enough to stop the fuel flow. Anyway I will go and work on a Briggs some bloke dropped off here last night
Fitting an F/C to a PT Super 24 base? Thats exactly the opposite to what I have done. My PT on a FC base seems to work well. Been going a few months now but not much growth during winter. Its quite a bit of work I found fitting these non standard motors to these bases but I'm sure its possible. My PT is fitted crossways like all PT's except those on 24's. I can not see that that makes any difference.
Its a pity we are not closer. I would gladly swap bases.
I still think that Suzuki would be worth a try. As you have said I do not think the power is much of an issue. Its the blade spimming mass that matters . Good to hear you are well to work even if it is on a Briggs.
Thanks Jeff, Hip is 100 times better, at least I got the Briggs running. I have fitted a F/C on a 24 PT base before but it was a lot of work, not sure I want to go that way again. As for the Suzuki's I can't seem to find them now so they may be all sold out. I could drive down to the warehouse and find out, it is only 5 mins up the road. I still have a couple of F/C bases here at the moment that I have pulled the motors off, but as they are older the bases have suffered more wear up around the front axle and that requires me making up bushes to fill up where the alloy has been worn away.
Hi Max, That is amazing, I can easily make one of those needles in the lathe, too easy. I did have quite a few of the briggs needle I was going to alter but I probably threw them out once I started using the viton needles. I will make one in the morning and see how it goes
I thought it's time to go out and give the nature strip a mow today. I haven't got any fresh fuel but luckily I still had just under half a tank left in the old FC Commando so I thought that should be enough for the nature strip. I also added about half a cup of what was left in the plastic fuel container and just gave it all a good shake around before trying to start it.
This mower has been sitting for 3 months, the last time I started it and mowed the backyard was when I recorded footage to upload on these forums and that was on the 15th of May 2019.
I turned the fuel tap on, let the fuel flow for a bit then I just pressed the primer bulb once to see if it starts. On the second pull it briefly started then stopped. Then I gave the primer bulb another press and on the next pull "VROOM". Away she went and never missed a beat until I finished mowing all the nature strip. Maybe next time I should try giving the primer bulb a couple of presses instead of just once.
Cheers!
Zip a dee doo dah, zip a dee ay, another trash picked Victa, hip hip Hooray!
Hi Converse, when a float needle decides to work they are usually very good, it is when they decide to act up it can drive you nuts, but once they settle they usually cause no further problems
Getting very close to giving up on these 2 strokes again, so sick of float needle problems continuing so many over the last week or so, fit new primer cap,new needle works fine for half an hours mowing and then the start pissing fuel out the primer cap. It can't be this bloody hard to get a float needle that actually works, Briggs and Chondas seem to be able to manage it easily. I won't be picking up any more mowers I'm done with it
My latest idea is to set up a bank of 5/6 carbies polish the primer cap seat with a cotton bud with Autosol on it, fit a new needle and fit a fuel tank above the carbies and leave them with the fuel turned on for a couple of days to see if any leak. At least in doing this I can feel fairly comfortable that when I fit the primer cap and needle to a mower it should not leak. Hard to believe I have to go to all this trouble just because of these stinking float needles. Such a little thing that brings a tough mower to its knees
I have been struggling for weeks trying to get a otherwise perfect SPFC TAC right. It had sat in my to do line since sept 2018 and finally got to it late last year.
This morning I went out and put a little bit of thin valve grinding paste on the end of a cotton ear bud, wacked it in the cordless drill and polished it up, pushing the cotton bud right up into the seat.
Hopefully it works when I get around to refitting the carby
Strange thing is it runs great when its running, but its a bugger to cold start; normally no less than 20 pulls in between removing the plug and cleaning it due to flooding.
Have been giving it a hiding cutting new garden beds in, along with starting retic ditches for me. Went through half a tank just starting it last time, which I struggle to understand how.
Fixed a PT with one of the worst floods I have ever seen last week - guy left the tap on for 15 minutes with a yellow needle and lost nearly half a tank again
I think you are using the primer caps with the chamfer on the seat so the needle will seal ,if not I can see the problem ,
Might be easier trying a pressure tester ,I was thinking of making one and using a Doctors blood pressure tester hand pump ,the pump is only a few dollars online and just hook it to a pressure gauge. That or just use a bike pump connected with a gauge.
The gravity feed idea should work it's just the time that it takes to wait.
I haven't had this problem ,if the cap leaks I replace the needle ,but I never buy new caps always just take a second hand cap off a mower ,I know there are a lot of problems with low quality aftermarket caps, the only way is to buy them from the same supplier once you know they are ok.
The pressure gauge would be a quicker test and is easier when testing the same needle in different caps.
I think you saw this video Norm showing the different types of caps that look the same on the outside.
I'm sure once you can get the caps and needles to the right specs you shouldn't have a problem Norm but that may take some work as you say polishing the seat with Autosole may help but with a pressure tester you can see the result straight away.
Hi Tyler and Max, It can't be this hard to just get a float needle to work. Max, I wouldn't trust a pressure tester in this situation, only thing I am interested in it testing the [Censored] things with fuel and the only way I can see to do this is to set up a rig with a number of carbs mounted on it and a fuel tank above it and just keep the fuel sitting on the seat for a few days. The Viton tip can swell a bit once it is subjected to fuel so at least being in the fuel it means I should be able to fit and know it won't leak in 2 days time.
Norm, what about throwing a few in a bucket of 2 stroke mix for a month or so to get max swelling out of the way
I reckon a great deal of this issue is related to the swelling. Install, runs fine. Shut off engine then turn off the fuel tap - means the needle is at full height; the viton expands and catches in the seat (best case sticking, worst case damaging it).
I personally run them a little while after turning the tap off (but don't let them rev out at the end) and don't tend to have issues - but when I do I have a spate of them.
Max, I also find the old caps best, but they are progressively getting thinner on the ground. GA spares ones are useless, Victa genuine passable and Carbymasters are better, but still none are perfect.
Hi Tyler Only way I'm going with this is getting each primer cap and needle matched together tested on the rig and then fitted to a mower so I have proven that that particular pair work and will shut the fuel off. No other way can I see it working
If the Viton is swelling I wouldn't bother using them ,I would just machine up some brass needles on the Lathe as that's all some Stromberg carburetors ,early Villiers, and some motor bikes etc had and those needles and seats lasted decades with brass on brass.
60/40 brass has a density of about 8250 kg/m3 as opposed to mild steel at about 7850. Maybe the extra weight would help.
However I believe part of the issue is related to the fact it is a brass seat pressed into plastic; you can often see they are crooked. This is where viton shines as it will help seal a crooked seat.
There is also the issue with making the brass ones; stuffing around with a lathe with a piece of brass round stock. Even though I love 2 strokes, its just easier to throw a new carby on a chonda and put that on the deck
Hi Max and Tyler, I have to pick up some 1/4 inch tees tomorrow and I can connect up the 5 carbies to the fuel tank and see what happens. Each seat has been polished, new needle and primer cap. At least if any leak I can see straight away which one it is.
Ok so now I have the proof, I set up 5 in a row, turned the fuel on and 3 out of the 5 leaked. That is brand new primer caps from the Carbymaster so they are supposed to be the improved type and I polished the seats with Autosol and 5 new needles. Hard to believe all other manufacturers can make float needles that work and we can't get anything to work on Victas.
Now after a further polishing of the seats on the offending caps I now have 5 sitting there with the fuel left on and only a minor weep on one of them. Now I will leave them there with the fuel turned on for 24 hours and see if any start leaking. Annoying that I have to go through all this crap just to ensure these things won't leak somebody has picked a mower up.
Hi Tyler, I'm fairly convinced the problem is in the seat more than the needle. I now have 5 needles sitting there and holding fuel with the tap left turned on for 24 hours. I have polished up all the seats with Autosol on the cotton bud and I'm now fairly comfortable I could fit these to any mower and not have problems and even comfortable that if the fuel is left turned on it won't cause issues. You can only tell people so many times to make sure the fuel is turned off. Now my next test will be on all the needles I have in the reject container to see if I can get them to hold fuel as well. That will be interesting and hopefully polishing the seats in the caps will fix it.Another thing I have noticed with polishing the seat is that every needle moves up and down without sticking in the seat. It was always 50/50 before. Stay tuned I think I have solved it.
