|Stuart Turner 1.25hp petrol two stroke
Post Number: 1
|Posted on Friday, August 27, 2004 - 03:59 am: ||
Sorry total newbie question here!
Just thinking of buying a small old clinker runabout. It comes with a Stuart Turner 1.25 petrol two stroke.
I have a collection of old sailing dinghies....but engines are a completely new area for me.
How do I find out more about the engine...and are there any particular things I should look for before I buy it. It starts first time....even though not started for a couple of weeks. It pumps water through the cooling....it engages gear in forward and reverse. The throttle is slipping....but that seems simple enough to fix. No obvious knocking....in fact seems very quiet indeed.
Some mates have been rather disparaging about the likelyhood of it being in any way reliable....but it seems to chugg away nicely enough. However owner was not very happy about taking her off moring as tide was running hard....and he had not run her for a few weeks....
I guess what I am asking is....Do they run and then stop....overheating?
The boat is reputed to be from the 1940s.....but what age is the engine likely to be? Sorry don't have serial no with me at present, but will post if I go ahead with the deal.
Anybody know what the spares position is with these 1.25hp petrol two-strokes?
Is there anything else that I should know or be aware of?
big thanks in advance!!
If I go ahead with the purchase, I guess I might be asking you lots more questions.
|Posted on Friday, August 27, 2004 - 06:07 am: ||
Can't think of 1 1/4 hp Stuart - Could it be a 1 1/2 hp R4M (with reversing box) or R4MC (no reverse - centrifugal clutch)? If so parts are available from
Not cheap, but at least they are there. They also hold the original factory day books so can provide a date and possibly original customer for your engine from a serial number.
These engines were in production from the mid 1930's until the 1970's and thousands chugged away reliably for years on municipal boating lakes and day boat hire fleets. I believe there are still a few in such service, but the high cost of reconditioning tends to mitigate against their retention in this throwaway age.
Post Number: 2
|Posted on Monday, September 06, 2004 - 08:07 am: ||
Thanks for the info:
I have gone ahead and bought the boat and she seems great. Took me a little while to get the hang of the engine.....and I still have many many questions. If anyone has any ideas or info, I would be very very greatful.
Engine is a Stuart Turner 1.5hp R3M with reversing box. The serial number on both engine and gearbox is 41970
OK....a few questions:
What ratio of oil to petrol on an old engine like this. I am currently using 1:20....is this OK.
What oil should I use in gearbox? How much?
I am told there are problems with overheating due to blockages in the cooling water. Is this easy to check.....clean.... At present there seems to be a healthy flow of water coming through the system. Water is hot....but not so hot that I can't keep my hand in the outflow.
Engine came with a B6ES spark plug fitted but there were a number of old plugs which were B5ES. Anybody know what is correct plug for this engine?
I seem to be doing OK with starting from cold...but not finding it so easy from hot. Present system is to turn on fuel, pump rubber bulb (like outboard) until stiff. Tickle carb until petrol spurts out of carb.....set throttle to approx half and turn over....seems to either start first swing.....or not at all. Normally starts though.
Starting from hot harder though. Currently just setting throttle to low, turning engine over, opening throttle a bit, turning engine over...until with a little luck she catches. Problem seems to be floodding, when I have to pull plug, clean.....wait ten mins and go through the same exercise.
There are two adjustable bits on the Stuart Carb, I have not played with either yet. What do these do? I could explain more, but I guess you know what I mean.
Someone has suggested that the Stuart Carbs are not very reliable and replacing with an Amal is a useful mod. Is there any truth in this?
Is it possible to get hold of a owners manual....or servicing manual?
I have no idea when this engine was last serviced...what things should I check? what items should be serviced?
Anyway I do hope someone can help me a bit with these points....the engine is just geourgeous....and I guess I might work most of it out....but would love to know I am not doing anything that might foolishly damage it.
Strange thing....when when I went to see her, the seller was showing the boat to me and another possibly buyer and they were saying....lovely boat....pity about the engine....maybe you could pull it out and put on an outboard. When I got her home to home on the river, I got lots of ribbing about not forgetting to take some paddles and flippers to get home with....but so far she has not let us down.....now where is that wood!
Thanks in advance
|Posted on Monday, September 06, 2004 - 10:38 am: ||
I don't have manual for R4 marine (again, try fairways) but that for the stationary version reccomends 1/3 pint oil to 2 gals of petrol - ie 48:1.
Stuart carb is pretty simple and should give no trouble unless very worn. It has the advantage of being all brass rather than the nasty die-casting alloys of most of the competition. I think the eventual substitution of an Amal carb on the later engines had more to do with cost than the quality of the instrument. I can only think of one adjustment (unless one counts throttle stop) which is the air cap. This is screwed in or out to adjust the mixture strength - leave it alone if the engine seems to be running ok.
Your cold starting drill is Ok and hot starting problems are one of those two-stroke things - turning off fuel, opening throttle wide and giving a good twirl should help it clear its throat. It will probably then fire and frustratingly die before you can get the fuel back on!
Cooling flow sounds ok, though there is sometimes a possibility of localised overheating due to scaling of the waterways. Again I would leave well alone unless there is evidence of a problem.
I'll leave it to someone else to advise on gearbox oil, not having the right manual.
Nice to hear of an S-T engine being used as it should.
|Posted on Monday, September 06, 2004 - 11:15 am: ||
Just remembered that internal fire site has R3M manual (incorrectly ID'd as S3M). You'll need to register before you can download it (now required due to some low-life ripping off free content and selling it on ebay) but it's worth the small hassle.
Post Number: 109
|Posted on Tuesday, September 07, 2004 - 08:13 am: ||
As expected similar advice for starting cold and hot applies to my P55.
My R3 manual says to use Champion L10, Lodge C14 or KLG F50 (14mm plugs). IF running slow for long periods eg fishing and the plug tends to oil up then use a hotter plug such as Champion L8 or Lodge CN.
I suggest you run some fresh water thru the engine at the end of each use eg as you return to shore/boat ramp - to flush out the salt water - leaving it full of fresh water - as rust scale from fresh water immersion is much finer that from salt water. It's that coarse scale moving around that can block the narrower passages.
While your pump is not the same, (for others) in 2 P55 water pumps that I've restored I found the cast iron section of two P55s blocked solid with rust. They both came from seized engines. On the P55s the water pump comprises two sections - bronze front and cast iron rear section. It only takes a regular poke with a piece of wire thru the valve access point (remove vale cap) ensure that the water passage is kept clear.
|Posted on Friday, October 08, 2004 - 08:05 am: ||
I also have a Stuart Turner R3M. This is the 1.5hp Stuart Turner marine engine with forward and reverse gearbox.
The recommended gearbox oil is SAE30 Approx 1/5th of a litre or 1/3rd of a pint. Fill through the filler plug on top of the gearbox casing to 'MAX' on dipstick. The oil takes a while to run through to the section containing the dipstick so take care not to overfill.
Re. fuel mixture. 1/3 pint of oil in 2 gallons of petrol as Nick says or (20cc in 1 litre) is the recommended fuel to oil ratio, so if you are using a 20/1 mixture you are probably oiling up the plug.
When starting from hot do not allow fuel to squirt out of the fuel bowl. Just turn on the fuel and crank. I find if the engine fails to start or just stops after running it is usually a fouled plug. I just remove the plug, clean the gap and plug carefully with a rag and the engine always starts immediately I replace the plug.
The Stuart Turner R3M is a beautiful little motor. They are still in use today in hire boats in England and are well worth the little bit of extra care and maintenance required.
I have installed mine in an old (1918) restored wooden open boat (Towns boat originally built in Newcastle near Sydney Australia). It is 20 feet LOA and 5 foot beam, and the R3M pushes it along with ease.
I always run fresh water through the engine after an outing in the salt water. If the engine is not to be used for any length of time a lay procedure is recommended.
If engine is not used for several months it is wise to empty the petrol tank. In the course of time the more volatile fractions of the petrol are liable to evaporate leaving a gummy deposit that can clog pipes, jets etc.
I would be also interested to know what size prop you are running? Is it a 10" X 9" ie 10 inch diameter by 9 inch pitch?
Hope this is all of some help
Post Number: 1
|Posted on Saturday, January 15, 2005 - 07:27 am: ||
We are reconditioning a P5 with stuart turner reverse gear. Does anyone have a drawing showing the section through the gearbox. the reverse unit will not slide and apply the cone brake, I would really like to see what we are dealing with inside here before it gets persuaded to move by a series of ever increasing hammer sizes.
Post Number: 1
|Posted on Wednesday, May 03, 2006 - 05:38 am: ||
I am new in this area. This is my first time that I havebought a boat. This has Stuart R3 engine I think??? I need some service tips. The machine seems jammed because it has been not used for several years app 10 yrs- any help is appriciated