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Zak

Questions on running Ohlsson & Rice engines

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Thought i'd start a new thread for this, my main question here is once you get them running, what would be the best way to shut down an ohlsson & rice engine (or any 2 stroke/4 stroke engine?)

 

Iv'e heard the best thing for all engines is to turn off the fuel valve and let it just run out of fuel?? 

but since these ohlsson rice engines mostly don't have on/off fuel valves, what would be the next best thing? spark plug wire needs to be screwed on so for me that's a no go, another way i think would be to just fully close the choke - but could this cause any damage/issues for restarting later on?

 

Also some on the front of the engine ohlsson rice recommends something like a gallon regular gas to 3/4 pints outboard oil - whats the difference between regular 2 stroke oil and outboard oil and are they interchangeable???

i researched a little bit into 2 stroke outboard oils with the tcw-3 rating and all that, some websites said they were a better quality oil, some said they were worse! ....to add to my confusion - the regular  2 stroke oil iv'e been using (for lawnmower) has apparently been rated at tcw-3 - even though its not outboard oil???

 

Hope this makes sense! :)

The auto store looked at me like i was a madman when i asked them what tcw-3 oil was LOL :P 

Edited by Zak

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For long term storage draining the tank & running till all fuel is gone was recommended in the winterising procedure.

 

There are two ways to stop the O&R engine, one is the brass stop switch on the back of the magneto plate (exhaust side) or a remote stop switch (used on some tools), both of these short-out the primary of the magneto. The second method is to close the choke (as you mentioned). On early engines there was an optional third method, a shorting strip for the top of the spark-plug, shorting the spark-plug can be used if other methods of stopping an engine have failed (usually with a well insulated screwdriver).

 

Here is a picture of the brass stop switch,

SAM_6168a.jpg.c76ebd9b775d76cb20707b27dbe92529.jpg

 

And the (optional) HT shorting strip on an early engine,

SAM_7728a.jpg.6d0b2afcf0143cef41c77d1af47156c2.jpg

 

David

 

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Modern two stroke oils are much better than the oils that were available when these engines were made, mixing to the ratio on the starter decal with modern oils will result in a very smoky exhaust, using too little oil will result in dry bearings & premature wear.

 

Using a 32:1 mix of good quality AIR cooled two stroke oil should be good, I have been using Stihl HP oil (for all my two stroke engines) which was recommended by someone I know that uses two stroke chainsaws regularly.

 

Both outboard oil & #30 SAE oil (the modern equivalent is NOT suitable due to the additives used) have been mentioned in instructions for these engines over the years.

 

David

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Thanks heaps david! :) ahhhh so i see....heard about that stop switch - seems like mine has one, but knowing me, somehow i'm sure il'l accidentally bend the metal lol - i'm not at all familiar with electrical systems either, but couldn't that end up going back to the coil/condenser  and damaging it if it was stopped that way? or does the plastic around the stop switch stop that from happening? (no idea there lol) Anyway seems my best bet would probably be closing the choke :P

 

And ahhhh didn't know about that! looking at the numbers now i see what you mean, they recommend more than double the oil than in the 32:1 mix!! lucky i haven't mixed the fuel yet thats for sure lol -  i'm probably wrong about this, but running with too much oil in the mix would dirty the spark plug quicker right? hmmmm il'l try the 32:1 mix :D

 

so then you could use either provided the right mix??? now i'm reading more apparently outboard oil or tcw-3 rated 2 stroke oils are appatrently "detergent free" but  run more smoky....yeah i'm totally lost on this part lol

 

 

 

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Another question - just me chickening out a little bit on having to disassemble the entire engine haha - (since some small parts of the air intake foam filter have made it past the intake body) - does the engine really need to be all disassembled and cleaned??

If its run - wouldn't the foam just burn out with the combustion cycle and either carbon up slightly or ideally - go out the exhaust???

Would a good few minutes run with fresh fuel clean this out so to speak??

(now i know with dirt, dust, or sand in the engine it'd be a different story since they don't burn up, but foam?)

 

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No damage will happen to the coil or condenser from using the brass strip stop switch, it simply shorts out the primary winding of the coil to the engine casing, the primary windings consist of a small amount of turns of thick wire. Magneto coils usually fail on the secondary (high tension) windings, which consist of a lot of turns of very fine wire, failure is usually due to water ingress/insulation breakdown or corrosion of the wire (fails open circuit).

Battery coils are a different matter all together, the primary windings can burn out if energised continuously.

 

Too much oil will result in a very smoky engine and would likely need the spark-plug cleaned more often.

O&R stopped recommending Outboard oil around 1964 to reduce the amount of carbon build up over time.

The thing to worry about with modern oil is the additives in some of them, TC-W3 (NMMA trademark) is a marine certification standard (although that doesn't mean you can't use it for non-marine applications), you would probably get good advice from someone with lots of experience at a garden machinery repair shop, instead of big chain auto/car stores (where the sales staff often know nothing about the stuff they sell).

 

The small bits of the filter foam can; get stuck in the feather valve preventing it from closing and cause premature wear/damage the bearings in the same way as dirt, grit or sand can. The oil in the fuel helps it stick to everything inside.

It all depends on how much of the old foam got sucked inside and how far it got, which is difficult to tell without further examination, I don't know if anyone on here has managed to clean the old foam out without disassembly.

I usually dissemble mine anyway, to make cleaning the parts easier, identify & replace any damaged or worn parts, renew gaskets and to clean & re-grease the bearings. I've not rebuilt any O&R's with a gearbox yet though, but there is a completely dissembled Chicken Power bike engine with gearbox still to do (was bought like that).

 

David

 

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Here is a picture (which I'm sure I've posted before) showing the inside of the crankcase from a Turbair engine of mine that has ingested lots of the old filter in the past (not run by me), I should really investigate it further to see what condition the cylinder is in.

 

David

 

SAM_5103e.jpg.5d1296dce839e32ea5de5c1ed1446327.jpg

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Awesome as thanks david!!

 

Ahhhh so i see ....seems like disassembly is my main option now - disassembled air intake, exhaust, carb looked brand new inside so i didn't end up taking apart, put new fuel lines......annnddd  still didn't suck fuel....gotta be blocked either on the tank inlet or carb inlet...either that or i might see if i can rig up a  temporary fuel tank above the engine so the fuel just gets gravity fed...my only real other concern with disassembly is a lot of the screws are easily damaged when undoing/redoing them up....only luck iv'e had is to use a lot of "WD-40" and similar penetrating oil spray lubricants to make it easier to undo them and reduce damage to the screw heads but theyr'e still getting damaged quite easily :(

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Was it fitted with the base fuel tank? If so, there is a fine mesh filter inside at the bottom of the fuel pipe, the other two pipes are linked together (preventing an airlock at the opposite side to the filler). It could need cleaning or the fuel line maybe connected to the wrong pipe.

 

It should be possible to remove the screws without damage providing the screwdrivers fit properly, early engines used slotted head screws & later ones have Phillips head screws (Pozi-Driv screwdrivers are a poor fit and can damage Phillips screw-heads). They are sometimes replaced with whatever a previous owner could obtain or bodged with incorrect screws. Penetrating oil/fluid usually helps with anything tight or corroded as you mentioned.

 

David

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Hmmmm yeah the fuel tank is just under the engine/sort of built into it -  hmmmm if thats my issue, how exactly would can i clean it? 

but yeah, got one fuel line goes from one side of the fuel tank to the other, the other fuel line goes from fuel tank to carburetor - neither have any fuel passing through them :(

 

and ahhh yep mostly Phillips head screws, but yeah seems the penetrating oil is the way to go then :)

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I'm still a little confused, did you service the carb?

You can check the carb primer works by attaching a short piece of fuel line to the inlet, put the open end of the fuel pipe in some fuel and see if it will pump fuel when pressing the primer button. If it doesn't pump fuel, check the ball isn't stuck to the valve seat (they can stick with dried out old oil) and that the diaphragm is in good condition (flexible with no cracks) if you haven't renewed it of coarse.

 

As for the tank, only one pipe goes to the bottom of the tank, that is the fuel pipe and has the filter, the other two pipes are bridged to prevent an airlock and are not for fuel to pass through.

You can check if they are blocked by part filling the tank and tilting it vertically (with something underneath to catch the fuel), cleaning can only really be done with fuel, try leaving some in it for a few days, or use or carb cleaner etc down the pipe.

If there is a lot of dirt in the bottom of the tank I also put some nuts in the tank with the fuel and shake it to dislodge the dirt. Pour out the contents and repeat if necessary.

 

David

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Thanks David! :) sorry for the late reply, couldv'e swore i replied unless it didnt go through :( 

But yeah ahhhh sort of.....undid the carb and took the gaskets off but didn't actually take apart the arm mechanism,  seems to me like both the ball and fuel line may be blocked - nothing coming out of either but will definately try trick that with the carb primer :D 

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