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Roy Jones
Member
Username: royjones
Post Number: 7
Registered: 10-2006
| | Posted on Sunday, February 18, 2007 - 02:02 am: | 
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Hi everyone, Further to the first launching and subsequent runs, I am slowly getting to grips with the S/T. I've found they don't like idleing for any length of time as it fouls the plugs. Had a great run up the Pelorus river today and it does 3.3 kt at minimum revs which is cruise for the other boats so after a while it began to backfire spectacularly, blew the spark arrester out of the carb. Any it died and I swapped the plugs. They were fouled and pre-igniting the fuel. After that had to give it some hard work then slower for a while. On the way back it ran perfectly, mostly mid range but shifting the revs seem to be what it likes. But I am thrilled with it and building more confidence in it's reliability, I don't want to go too far until I am sure it will get me home but I am learning their idiosyncrasies. Cheers Roy |
David Stott
Member
Username: david_stott
Post Number: 17
Registered: 06-2005
| | Posted on Sunday, February 18, 2007 - 05:42 pm: |
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Roy, My P55 will idle all day and never fouls the plugs. Could your engine be running too rich or have too much oil in the fuel? Also harking back to recent discussions re oils in the last couple of weeks on this site, are you using ordinary engine oil, which does not burn? I am a user of the modern 2 stroke outboard oil, and I don't have a problem with oily plugs. In fact I can't remember the last time I removed the spark pugs, and I do plenty of slow speed work in festivals/parades etc. |
Roy Jones
Member
Username: royjones
Post Number: 8
Registered: 10-2006
| | Posted on Sunday, February 18, 2007 - 11:07 pm: |
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Hi David, thanks for your comments, I am intrigued at your using 2 stroke oil, I did try it first up and it gave plenty of blue smoke so I promptly changed to SAE 30 and now it burns clear and doesn't smoke unless at low revs. I am now scupulous with determining 50 : 1 ratio, in 20 litres of 91 petrol I put 400ml of oil. Re the running too rich, you could well be right but I have compared the main jet to the size in the manual and it is correct, however there are two other smaller ones below and facing the front which I presumed are for the idle speed but I don't know what to do with these ones. I am very much encouraged that your motor will idle for long periods as I enjoy cruising in confined waters at low speeds and it is disconcerting when it stops unexpectedly. By the way, what is the difference between a P55 and a P66? I went for a high speed 2 hour run today and it ran perfectly the entire time, it does nearly 7 kt. Throttle at about 80%, 100% makes no difference. Once again, thanks for your comments Roy. |
Jeremy King
New member
Username: captain_pugwash
Post Number: 1
Registered: 01-2007
| | Posted on Monday, February 19, 2007 - 01:51 am: |
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In my P66 I use Castrol 2 Stroke bike oil, runs like a charm, some normal 2 stroke smoke usually during accelleration or rev changes. I wouldn't use SAE in her.
I think a P55 has 8hp and P66 10hp ... or somesuch.
Happy boating
Pugwash and crew. |
David Stott
Member
Username: david_stott
Post Number: 18
Registered: 06-2005
| | Posted on Monday, February 19, 2007 - 05:50 pm: |
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Roy, I use Castrol oil for water cooled Two stroke outboards. Dont use stuff for mowers etc.
Like Jeremy's comments, my engine emits hardly any smoke.
Not sure what carby you have because mine runs the Brass Solex and there are no adjustments on it. Only way to fix a richness issue is to alter the float level by rotating the carby relative to level. Someone with experience with your carby may be able to add more about the screws you mention. (Tim M, Peter O)
P66 has coil ignition rather than magneto on P55. P66 is also rated at 10hp I think whereas P55 is 8hp.
Other experts (Tim M) who read this site will be able to add more differences.
I find that about half to three quarter throttle is plenty. No more speed available on full throttle. This will have something to do with boat design as well, as my boat digs its stern in on high throttle settings.
David. |
Roy Jones
Member
Username: royjones
Post Number: 9
Registered: 10-2006
| | Posted on Tuesday, February 20, 2007 - 05:47 am: |
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Hi Guy's, thanks for the very helpful comments. I found out today that there are two types of 2 stroke oil, for outboards and for chainsaws etc, I didn't have a clue about that. Another theory is that the petrol today is totally different from the old fuels when SAE 30 was recommended. So I will try both 2 stroke oils and compare. My Carby is an AMAL R.622 and has a no 90 main jet fitted, std as per manual. However, like you say David, I wonder if any of the more experienced S/T guy's could advise what is the importance of the two smaller jets at the front of the carby are. One is horizontal right beside the manual prime button and the other slightly below and angled upwards. I am sure they have a big bearing on my poor idleing reliability. The motor used about 12 litres of fuel yesterday for 2 hours running at 80%, thats roughly correct from the manual.I do have another spare motor and I could try the carby off that one as a comparison, it is a Solex, just occurred to me! Cheers, Roy |
David Stott
Member
Username: david_stott
Post Number: 19
Registered: 06-2005
| | Posted on Wednesday, February 21, 2007 - 05:22 pm: |
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Roy you could try the solex as a comparison. There will be no adjustment required apart from getting the float level about two thirds the way up the tube. Check this by putting the top back on at an angle to normal so you can see the fuel in the choke tube.
Then altering the angle of the carby. There is an adjustment for that against the engine block.
Remember to have you boat in running trim if it is on a trailer.
David. |
edward parker
Visitor
| | Posted on Saturday, February 24, 2007 - 02:34 pm: |
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On the Amal carbie the horizontal screw is the air bleed screw for idle mixture and the one below controls the idle running speed.
I would go for outboard oil at 50:1 mix.
The Amal is infinitely abjustable with the rings on the needle along with different slide cut outs. Getting it set up correctly takes a little time but is worth every minute as when they run well they sound superb! |
Roy Jones
Member
Username: royjones
Post Number: 10
Registered: 10-2006
| | Posted on Saturday, February 24, 2007 - 02:45 pm: |
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Thanks guy's, I fitted the Solex yesterday and took it for a run and although it ran in the workshop, when I launched it it would only run with great difficulty. I fiddled with the adjustments for a time but couldn't get it to run anywhere near as well as the AMAL so came home and refitted the AMAL again. Edward, your info on those two adjustments are great thank you, just what I was looking for so I will have another go this avo and see if I can get it idling better. I had a feelling that these were important but without knowing what are the effects I am in the dark. I will let you know this evening how I make out but I am pretty optomistic now, thanks a lot guy's, cheers, Roy |
edward parker
Visitor
| | Posted on Saturday, February 24, 2007 - 04:17 pm: |
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There is a very useful little leaflet on the Amal 600 and 900. list no117/3 issue no 5. (IMI Amal ltd)
This gives the sequence of tuning and hints on how to alter any adjustment issues with main jet, pilot jet, throttle cut away and needle position.
I would perhaps advise a 'Google' for an Amal spares stockist and get hold of it. |
Roy Jones
Member
Username: royjones
Post Number: 11
Registered: 10-2006
| | Posted on Sunday, February 25, 2007 - 01:35 am: |
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Hi Edward and guy's, thank you again for the info and I will go and have a look at the Amal site for further clarification once I leave here. I took her out this afternoon with the Amal fitted and once out of the main drag I began adjusting the two screws and instantly apparent it was way out of adjustment. By tweaking one then the other I think I have got it almost dead right and it's running sweet as now. Did about 2 hours at little more than and idle and not a hint of hesitation, I am now really confident in her reliability. It starts with about a half crank from cold and a little more when hot. Next weekend is the Lake Rotoiti Antique & Classic boat show so I want it running right for then and I am sure it is now. Once again, thank you all for the help and what a great site for Stuart Turner info. Cheers everyone, Roy |
Jeremy King
New member
Username: captain_pugwash
Post Number: 2
Registered: 01-2007
| | Posted on Sunday, February 25, 2007 - 05:43 pm: |
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Yes Roy,
When you get them running well it's like having your first bowl of Coco pops!
Well done
JK |
edward parker
Visitor
| | Posted on Saturday, March 03, 2007 - 06:04 am: |
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Burlen Fuel Systems are the present owners of Amal carbies. Spares can be obtained from their website at; www.burlen.co.uk |
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