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Message |
    
Claude Fields
Member
Username: claude
Post Number: 8
Registered: 09-2012
| | Posted on Friday, February 01, 2013 - 12:31 pm: | 
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I have a 5 HP Acadia. Should the spark fire at top dead center as an intial setting? |
miro forest
Senior Member
Username: miro
Post Number: 660
Registered: 11-2001
| | Posted on Friday, February 01, 2013 - 10:13 pm: |
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I think you'd like to retard it at least 5 to 10 degrees, i.e. it fires at least 5 to 10 degrees of rotation of the flywheel AFTER top dead centre.
That way you should avoid a backfire and it will be easier to start.
Once it is running, you can shift the timer to top dead centre and then once warmed up, you can advance it a bit, but if there is no load, you'll likely find that the top dead centre will be OK.
miro |
Claude Fields
Member
Username: claude
Post Number: 9
Registered: 09-2012
| | Posted on Wednesday, February 06, 2013 - 10:10 am: |
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Thanks Miro. I'm a real novice at this, and this will help. |
Eric Schulz
Senior Member
Username: eric_schulz
Post Number: 78
Registered: 01-2007
| | Posted on Wednesday, February 06, 2013 - 05:44 pm: |
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It surprises me that no one has commented on this incorrect timing information.
No engine ever built has been designed to fire at top dead centre. That is for starting only. All engines need advanced spark when running. I am not familiar with the Acadia, but if it has a variable timer, start at TDC and when running, advance the spark to where the engine sounds happiest.
There is absolutely no need to ever have the timing to be after TDC.
Engines running with retarded spark are a pet peeve of mine. This makes the exhaust much louder and makes the engine run hotter.
I have read that some boat operators slow their engines down by retarding the spark, not closing the throttle. This is like keeping the accelerator pedal on the floor and regulating the speed of the car with the brakes!
Eric |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 760
Registered: 07-2002
| | Posted on Wednesday, February 06, 2013 - 06:21 pm: |
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The Acadia is a reversible ignitor engine, I don't believe you can get below TDC, probably a little above is the best you can expect. We know late timing is not the most efficient way to run a motor but it's a lot easier to adjust speed and direction with one lever. |
miro forest
Senior Member
Username: miro
Post Number: 671
Registered: 11-2001
| | Posted on Friday, February 08, 2013 - 12:10 am: |
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Eric, the ONLY way to get any speed control on a DisPro, is by moving the timing of the engine. The throttle setting has practically no effect.
Trying to start a copper jacket DisPro at TDC will likely cause a backfire and will damage the ( very expensive to repair) pull recoil starter mechanism.
Once running, , yes I agree , advance the timing.
But at a show , with no load on the engine, you'll get overspeed and possible really get into trouble.
miro |
Claude Fields
Member
Username: claude
Post Number: 10
Registered: 09-2012
| | Posted on Friday, February 08, 2013 - 10:17 am: |
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OK Guy's here is the deal. I'm new to this hobby. I'm rebuilding this engine and I'm ready to fire it. I had to make a new trigger for it that actualy will adjust the timing and I need a starting point. I thought in my mind TDC would be the place to start. I don't think this engine will ever be used in a boat. |
miro forest
Senior Member
Username: miro
Post Number: 672
Registered: 11-2001
| | Posted on Friday, February 08, 2013 - 03:47 pm: |
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Hi Claude, welcome to the group.
Can you post pictures of the engine?
( if you have trouble posting the pictures, there are others on this site who can do that for you, if you email the pictures to them, eg Richard D and Ernie or even me)
Or at least tell us what it is.
There are many folks here who have quite a variety of engines, and I would not be surprised if some one has one like yours.
There's nothing like a bit of experience to help you along.
You might also review the discussion in the 1 cylinder Gray engine topic.
There's good stuff there.
miro |
Michael Bashaw
Member
Username: mbashaw
Post Number: 12
Registered: 11-2010
| | Posted on Friday, February 08, 2013 - 05:41 pm: |
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I put my restored DisPro in the water last summer for the first time, but I never got the engine running. Now I wonder if I had the timer too retarded. It ran once for about 30 seconds, and I have a video of it, but that was it.
Is there a way to upload to the site? I would love comments. |
Claude Fields
Member
Username: claude
Post Number: 12
Registered: 09-2012
| | Posted on Friday, February 08, 2013 - 06:06 pm: |
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Here is a picture of the engine I'm working on. A little history. Piston was froze in block. I used hydraulic pressure and time to move the piston. I took this on and work at one step at a time. Many things have been cobbeled up over time so as I find issues I try and fix them with lots of research and reading. This site has been one of the best resources as well as help from the Fisheries Musem in Nova Scotia. I think I spend twice as much time reading and searching compaired to actual hands on time. I think I'm close to firing her up. The plan is to get her to run, than maybe go back over her and give the old girl a face lift. I have more pics and lots more to say. I sure do appreciate the help and suggestions. This is a great hobby. |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 764
Registered: 07-2002
| | Posted on Friday, February 08, 2013 - 07:04 pm: |
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I don't own one of these so I'm just trying to picture it and think it out. The engine is usually set up so it's reversible, that means that the eccentric has to be centered at TDC. At TDC you will have no movement of the trip rod so you have to trip before tdc in either direction. If you are only running in one direction you can move the eccentric to retard the timing to after TDC, but it will be far advanced if you reverse it. If someone here has one of these maybe they can shed some more light on it. |
