timing of a silver (ws & wspc)

[Nudge]

I have been having some issues trying to get two silvers to run / rev to the same rpm.

The ws runs great it has a 3.5 :1 box with a 5 blade hydro fan and will pull 4000 rpm all day long.
Now the Wspc that is the one that is having problems.
I took the 4.5:1? box with a weed free 13" 4 blade prop off and put the 3.5:1 gear box off the WS on it. You would think that the Wspc power head would be somewhere the same now. But it is not! The Wspc will only pull 3100rpm?? So why is this.

I put both engines side by side in the wash down tank to look at them.
Swapped the carbs over (without changing any settings) still no change!
Then I noticed the D cut out on the mag base plate was in differant places.
At this point I have decided It has to have something to do with the timing!

I worked out where TDC was by welding a bar to the end of a sparkplug to stop the piston. Rotate the piston one way, take a reading, rotate it the other way, take a reading, devide number in half and it will give you BDC.... 180° from that is TDC.....Got it!

The timing on the ws is factory set to 40° BTDC

The timing on the wspc is factory set to 30° BTDC

So why is WSPC set at 30°BTDC and the WS set to 40°BTDC???? The power head on both these engines Should be the same???
The problem with changing the setting on the WSPC is where the hole for the retaining screw is. It is half a hole out!
How to fix that problem??? I turned up an aluminium slug cut a 5/16 x 26 55°thread that was a little over size and wound it in the hole.

More to come

[Nudge]

it is quite clear why the retaining screw kept slipping into the hole when the engine is set to 40°BTDC.

I took the boat and engine out for a test. Had a rev counter hooked up, Fired the engine up ran it up to 3000 for a bit to let it heat up a bit. Then it died!
The rev counter that is!!
At WOT the engine sounded like it was reving up to at least 4000 it may have been more. I was running a 5 blade hydro fan and got an a stady top speed of 16kph according to my GPS!

I think I might open up the rev counter and see if I can put a new battery in it. (not sure if that is what is wrong with it but it's worth a shot!)

[Collector Inspector]

There has been much discussion re "timing" over the years. Maybe search the site re that which may be very useful......or not as this type of thing has never really been resolved as a case in "How it should be".......

You said that you ran the engine and got how many Km/Hr?

Case in point if it sounded happy flat chat and also an easy start......................good enough.

"sounding happy" I can not explain, just my old ears sitting next to ANY Old Dear doing 100%. There is a distinctive machine whine/hum..........sorry just knowing by the sound how things are rotating?

Did you take a vid?

Regards

BnC

[headdownarseup]

Interesting...

From some of my stuff i do in the shed from time to time, the timing of these engines seems a little hit or miss, hence a noticeable difference in the "sound" they make at FULL CHAT. Some will sound "sweeter", some will sound "flat". A trained ear helps with this.
Some engines seem to be in the ball park of 40 something degrees BTDC, some are a little more, some are a little less.
The "dimple" that locates the locking screw is quite a fragile thing that becomes elongated over time and thus the timing will change.
Not only that, but the very end of the screw is not often FLAT for a proper location. Some are even cut to a point, as with some of the older motors, and some screws are more rounded at the location end.

It's a difficult thing to try and re-adjust with any degree of accuracy due to the crankcases being drilled for the locating screw. I've often wondered how accurate these holes were drilled in the first place.
I think you're onto the right way with this Nudge. Check and double check everything before you re-drill the hole.

Staying with timing, i'm having similar issues with my 50cc moped at the moment. Trouble is with this, being a chinese clone of something or other, any "performance" orientated parts are few and far between. Just like the seagull it's basically fixed at 15-18 degrees (thereabouts) with no possible way of altering the timing unless i elongate the locating holes in the stator plate which might give me a few degrees to play with.

Keep us updated with your progress. I'm keen to see the outcome with all this. (i've played a bit with cdi's before now with some success)

Jon

[Nudge]

Did you take a vid?

No I didn't. Im hoping to get out again today (this time in the 20 footer) I was in the 12 footer yesterday.

You said that you ran the engine and got how many Km/Hr?

The 16Km/Hr was in the 12 footer, I was by myself with next to no fuel and to be honest running running with the tide.

Check and double check everything before you re-drill the holeCheck and double check everything before you re-drill the hole

Up until I'm 100% happy, I won't be drilling a hole. I think the hole was initially put there in the factory so that the novice could take the engine apart and rebuild it and get the timing in a postion where the engine will run.

[cobbadog]

Brilliant story and results so far. Looking forward to hearing sore as it all unfolds. Imagine what could be done with an advance and retard set up like on the bigger outboards, an adjustable stator plate!

[croweater]

Been slowly catching up looking at old posts, have been playing with 2, 3 and 4 wheeled toys and giving the gulls a rest. We did a 2,000km trip five years ago I had set up four Century motors the same or I should say I thought they were the same. One was used for parts within the first few days, Two had similar performance and one performed better than the rest which bugged me, it sounded like timing as the exhaust note was crisp and it was a little harder to start needing 2 or 3 pulls. Trip over with I checked the timing and there was a difference so I changed the flywheel which made no difference, I suspected the backing plate locating hole in the crankcase but never looked further, will have to check it out.
John

[Hugz]

Didn't they play around with different porting configurations?