Hard to start Ruston PT

The Ruston PT I recently bought takes a lot of cranking before it starts. Once it starts it runs ok.
I've checked the timing and it seems fine, maybe just slightly retarded. I tested the spark and it is consistently strong. When I take the spark plug out after cranking it is often dry and made me think the Amal carbie needs a clean out. I did that and the jet was clear as were the other carbie parts.
I watched a few Youtubes and noticed on a Ruston PT or Wolseley WD that they give the carbie a really good prime. I tried that until fuel started spurting out the little hole in the cap on the amal float chamber. It didn't make any difference to starting. I adjusted the float on the needle valve so the fuel is abit higher in the float chamber - that has helped it run but didn't help with the starting.
Wondering if anyone else out there has some tips from dealing with the same issue and can enlighten me?
Regards Graeme

Sounds as if you've checked everything, only thing you havn't said about is compression.

My Wolseley I can start it off the flywheel but the Ruston PT I have is a bad starter but I've not had much time to look at it as it needs parts that I'm gathering to complete it.

Stu.

The first thing's i can think of is any air leak's all gasket's doing their job. idle speed to low. wrong mixture is to lean or to rich if rich the exhaust will be black if lean then harder to start as less fuel getting to cylinder.
That's all i can think right now.
Andrew

Thanks for your thoughts.
Compression I think is ok, perhaps it could be better.
I will fiddle with the idle when starting and look at that gasket suggestion - a leak would certainly not help.

Regards Graeme

As already said, it could be an air leak, or bad compression. What about your valve clearances? If your inlet valve isn't lifting enough then it will be hard to start.

I don't think idle setting will have much effect, as with most stationary engines that have a governor, they all start on full throttle.

My old Wolseley WD2 used to be a lovely starter. But it always needed full choke, then as soon as she fired up you could open it up. (I think so anyway, it was over 15 years ago now).

Another thought, air leaks might be from a sloppy throttle butterfly spindle, but there's not much you can do about that I'm afraid.

My PT is a right nightmare to start at times! I usually fill the float chamber BUT DONT FLOOD IT, then close the fuel tap. Mine will only start with no choke at all, lever forward towards the crankcase, and then wind like Hell until it fires! Then I move the lever back one notch, turn fuel back on and it will run all day long.......until I stop it and then the fun begins again. Mine has the Lucas mag, the Wico mag ones usually start better as the mag rotates at engine speed, the Lucas ones run at half speed. If bychance it floods then I might as well walk away from it for 1/2 hour!

Pete.

:chin:
Thanks for your advice. It has given me lots to check out.
My PT is one of the later ones and has the Wico A maggy - so that should help with starting.
I haven't checked valve clearances so will do that.
Going to buy some gasket material today and stop any air leaks around the carby.
Like most engines, it sounds like I've got to fiddle with start up settings too until I find one that works with this engine - all part of the fun but not always enough time in a weekend.

Regards Graeme

It's the worst part of an engine build or buying an un-known engine, is finding the best start settings and then try to remember them
The day I had my PT running I remember then setting were way out so I need to start again and do it by the book.

Stu.

Here's the update.
I reset valve clearances by the book - opened them both up.
Set timing by the book - advanced it.
Made a new gasket for the carby.
Good news is that it started much easier.
As you say Stu - I still need to find the little secrets to what will improve starting.
Thanks again guys for your tips.
Regards Graeme

Great news!

Well done Graeme now to find those little tweaks, it could take a while to find them, half choke, full throttle, different ways to swing the handle now where do you start to find the best position. :chin: At a rally a few years ago the guy next to me had a pt and it was the same, he took it home set it to the book had a bit of a fiddle then next day I thought it was a different engine it start well and ran spot on all day, unlike the previous day, so that's what made me think about returning it back to factory settings so to speak and start from there.

Stu.

I've been starting the PT from cold using different settings.
Best start yet from flooding the carbie, choke full on for one turn then back to half way and off she went.
Very satisfying. Will try again over Easter and make sure it wasn't a fluke.

Regards Graeme

Sounds good. I often find engines don't need full choke after flooding, basically because flooding is doing much the same thing as choking, in as much as it's introducing extra fuel.

When I helped Toby with his Lister I found it needed flooding, then turn the handle, she would fire up, then she would just struggle after the first few puffs, so hold the choke plunger down for a couple of rotations, let go & she would catch on nicely.

It's just a case of finding that balance, & often choking an engine won't let enough air in (depending on the carb & how it has worn over the years). They're all slightly different. Even the 3 Tarpens I've restored over the last 6 months or so have all been different to start. & my dad's old British bikes are the same, all different starting techniques.

Still, it sounds to me like you've got it sorted, good work

Graeme that's good news that you may have a way of starting your PT. I think we're all a bit spoilt now with cars with fuel injection where as a few years back with carb engines it was half choke 3 pumps on the throttle pedal and away it went but hot starting is no choke and pedal to the floor now whats strange when it comes to winter blah blah blah thing is these engines are similar and once you crack the starting code your sorted.
Looking forward to hear your results over the weekend as it could be a good starting point (ignore the pun LOL) for my PT with a similar problem.

Stu.

What plug are you using? I know some would say stuff anything in and it should run, but I've found Ruston's can be particularly plug sensitive. Try a Lodge CB3 or BBL if you have one or something with protruding electrodes. Don't think it will hit anything as the plug is up above the valves in its own little pocket. Just a thought.

Stamford24 wrote:What plug are you using? I know some would say stuff anything in and it should run, but I've found Ruston's can be particularly plug sensitive. Try a Lodge CB3 or BBL if you have one or something with protruding electrodes. Don't think it will hit anything as the plug is up above the valves in its own little pocket. Just a thought.

He loves his plugs this one.

Just wait 'til I see you next, I have a list of plug questions all ready & waiting. (always eager to learn something new as I'm afraid I've always just used any old plug as well )

I'm glad I put in another reply on this topic - always glad to consider new ideas and with everyone's brains combined the missing links start appear. I guess that's what a forum is all about
But don't believe anyone who says it probably also takes 4 engine enthusiasts to change a light bulb

Regards Graeme

Stamford24 wrote:What plug are you using? I know some would say stuff anything in and it should run, but I've found Ruston's can be particularly plug sensitive. Try a Lodge CB3 or BBL if you have one or something with protruding electrodes. Don't think it will hit anything as the plug is up above the valves in its own little pocket. Just a thought.

I have to agree there's to much "a plugs a plug" message being told to mewbies and it's causing all sorts of problems. A manufacturer designed the engine and picked the correct plug for the job, the only thing we should change is to a hotter or cooler plug.

Stu.

stationary stu wrote:

Stamford24 wrote:What plug are you using? I know some would say stuff anything in and it should run, but I've found Ruston's can be particularly plug sensitive. Try a Lodge CB3 or BBL if you have one or something with protruding electrodes. Don't think it will hit anything as the plug is up above the valves in its own little pocket. Just a thought.

I have to agree there's to much "a plugs a plug" message being told to mewbies and it's causing all sorts of problems. A manufacturer designed the engine and picked the correct plug for the job, the only thing we should change is to a hotter or cooler plug.

Stu.

Well I would agree to the first part Stu but not necessarily to the second. Yes manufacturers picked the best plug for their engine but that was under working conditions with everything like new. An off load engine can behave quite differently and one with a weak mag. You can sometimes get round these by substituting a different plug often very different from what the manufacturer recommended. Just check to make sure if its a protruding type that the electrodes don't get tangled up in the valves or piston

Just following up on the spark plug thing.
I went looking for Lodge spark plugs but the CB3 and BBL don't appear on ebay although one guy lists a heap of Lodge plugs.
What do you think about a replacement as advertised by timegreen880 on ebay who sell a KLG ML50 and list it as an equivalent to the Lodge?
Regards Graeme

There's a CB3 here http://www.ebay.co.uk/itm/LISTER-D-STATIONARY-ENGINE-SPARK-PLUGS-/321100785216?pt=UK_BOI_FarmingEquipment_RL&hash=item4ac3192640
The picture nicely illustrates the difference too as the Champion 8 COM is a Lodge C3 equivalent and a pretty standard plug for most stationary engines. The BBL is a single electrode equivalent of the CB3 as far as I know. The KLG ML50 may be an equivalent in heat range but it has a longer thread which would protrude into the combustion chamber and get carboned up making removal difficult or impossible without removing the head!

Greens spark plug co sell them but there not cheap, also if you click on them it will give alternatives, say the BBL well that's the same as a Champion D16 and the champion is £12 cheaper.

http://www.gsparkplug.com/shop/catalogsearch/result/?q=lodge+cb3&x=12&y=11

http://www.gsparkplug.com/shop/catalogsearch/result/?q=lodge+bbl&x=22&y=7

Stu.

Hi there, can anyone tell me in layman's terms how to set up timing on a PT!? Many Thanks in advance :-)

Here's how I went about setting up timing - someone else may be more precise or correct me - that's ok .
- On the flywheel there are two lines. One has the letters "TDC" (top dead centre) and before it a line with "spark"
I had to clean paint off the top of the flywheel to find the marks. I've also started pulling my PT down but have taken photos to show you.







- There's also a vertical line/arrow on the engine (see picture of round raised bit on engine block that I cleaned the paint off) that lines up with the flywheel marks. When you turn the flywheel and the "spark" line is right on top - the highest central point on the flywheel - it will line up with the line on the engine. Take the cover off the magneto and you should see the points in the magneto open. With the wico A impulse magneto you will hear the magneto click as you turn the engine over and the points open and you can watch where the "spark" line is when that happens.
- If it is out there is a bit of adjustment on the magneto mounts, other wise you will need to move the gears.
- More technically, you can check for top dead centre by turning the engine over - it is coming up to TDC and the firing stroke after it sucks in air and then compresses it - the piston coming to the top of the cylinder with fuel and air ready for the spark. The points open to give the spark in advance of TDC and that's what the spark line on the flywheel indicates.
- Don't forget the other things the guys have written in this blog about checking valve clearances etc too as that can also affect timing.

Give it a go anyway and if you have any problems share them back here - someone always seems to find an answer.
Regards Graeme

That's a good answer right there.

I would add that a magneto fires as soon as the points begin to open, literally JUST as they open. The old fashioned way to find this out was to use a small piece of cigarette paper in between the points. Put it in there when they are open, carry on rotating until they are closed, keep checking that the paper is tight & as soon as it goes loose it means they are just beginning to open, that's your firing point. You can do it by eye, although it's not quite as accurate, but will do to get you going. You can see the cam in the centre of the mag when you take the points cover off & you can see it opening the points.

Also, the fully open gap between the 2 points should be accurately measured with a feeler gauge (as should the gap in the spark plug) as these all effect things as well.

If your magneto gives a loud "click" as it goes round then you have an impulse starter. This click should happen at TDC. This is for easier starting, but not all engines have impulse magneto couplings on them.

One thing to add, make sure you are turning the magneto in the correct direction when timing. Check which way the engine will rotate it & rotate it that way. Try taking the points cover off & having a look inside whilst rotating it. Try to familiarise yourself with it & identify the different parts.