Home › Forum › Ask A Member › 1973 6Hp Evinrude Fisherman hard starting cold
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December 8, 2020 at 8:33 am #224594
hummm 3/4 throttle to start it ??? last question did you line up the cam and cam follower to ” just opening” the throttle plate” at START
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December 8, 2020 at 9:35 am #224597Cam & follower are lined up to the mark on the cam plate and there is no slack in the linkage. 3/4 is a tad high but it gets the job done – as long as you cut the revs as soon as it fires. See my next project below.
December 8, 2020 at 10:08 am #224599Hmmm, wondering if the modules are somehow retarding the timing/advance…. Which might explain its lack of power and strange needle valve setting… Wish there was some sort of grid on the flywheel mag plate showing advance, but there isn’t. You could use the timing light to see if the flywheel hash marks are falling between the two mag plate marks though….
December 8, 2020 at 11:19 am #224619maybe adjusting the cam a tad beyond “mark line-up ” with the roller would open up things a bit instead of going all the up to 3/4 throttle ???
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December 8, 2020 at 1:19 pm #224631Hi guys — ya aren’t going to let me give up on this are you.
Cosbyman — will try your suggestion.
Fleetwin, I thought of that too. I have checked the spark timing with a timing light and the spark fires with the flywheel mark exactly above the right most mark on the mag plate and never flutters at any rpm. Not Ideal but certainly within tolerances for an old motor. I tried to remedy this with an offset woodruff key (which I fashioned by hand with a file & hacksaw) to change the relationship between the crankshaft (piston TDC) and flywheel magnets. Offset OEM woodruff keys are often used in high performance engines to fine tune the relationship between the crankshaft and camshaft. You can see from the pictures of the home made key below that there was no discernable difference in performance (when applied in either direction) because there was only a couple of degrees difference. Would you suggest a greater movement of the flywheel in relationship to the crankshaft and not using any Key? If so, how much and in which clock direction because I don’t know which direction is advance or which is retard.
TomDecember 8, 2020 at 5:19 pm #224651I don’t know, Tom….I’d let you give up on it….I most always start those engines cold at 3/4 throttle. That way, there is no baloney. They START. Like you said, you just throttle it down as soon as it fires off. Now, at idle speed and warmed up, they should start at slow position with ease….
What was the compression again???
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December 8, 2020 at 8:19 pm #224666This brings up a good point….Usually, with the universal magneto, a sheared key will kill spark completely. But, using these modules eliminates the points, therefore the relationship between the flywheel/cam/crank is irrelevant when it comes to spark quality/intensity. But, the actual ignition timing will be affected. I’m not sure I understand where your flywheel hash mark falls in relation to the two hash marks on the mag plate. Both of those flywheel keys appear “sheared”, and will retard the ignition timing….Anywhere between the two marks is OK. But, in this case, like the CDII system, a sheared flywheel key will not show any different timing than a properly aligned/non sheared key. The keys you show in your pictures will retard engine timing, which may explain the running issues you are experiencing. I would put the standard key back in and retest, I’m thinking these issues will be resolved.
This is a good thread, using the modules can mask a sheared flywheel key….December 8, 2020 at 10:28 pm #224683Hi Fleetwin,
When I installed the offset key and got no change in performance I Removed it and re-installed the OEM key which has been in place throughout our thread here. The key in the picture is not sheared, but intentionally “carved:” that way to create an offset between the crankshaft keyway and the flywheel keyway by a couple of degrees. Install the offset key one way and it will retard the spark timing. Install the key in reverse position (upside down) and it advances the spark timing. I wish I could show you a diagram because a picture is worth 1000 words and you would see what I mean right away. With respect to the spark timing as it is now, with the original key and new modules- let me describe & bear with me because I’m not trying to be condecending. I don’t know how to send simple diagrams over the internet. I drew a crude picture – see below attachments. Picture in your mind or draw on paper the mag plate with the two timing marks in front of you. There will be a vertical line on the left and a similar line on the right about 1/2 inch apart. Half way between these two marks is perfect timing. If points are set perfectly, a timing light will show the boss mark on the flywheel to be in the centre between ( but above) the two lower timing marks on the mag plate on each revolution of the crankshaft. With the modules and OEM key, the timing light shows the spark firing when the boss mark on the flywheel is exactly over top of the right hand mark on the mag plate. I assume, without knowing for sure, that the spark is somewhat retarded. So my questions are as follows.1 by the picture #1 below, when the spark fires, which direction on the mag plate indicates an advanced spark, to the right or left of the double timing marks?
2 If I remove the key completely, can I alter the spark timing by clocking the flywheel keyway to the right or left of the crankshaft keyway? (I would test at low speed in a barrel for starting & running improvements after warm up. If a significant improvement is found I would have to find a way of securing the new crank & flywheel relationship without a woodruff key).
3 by the picture #2 below, If I wish to advance the spark, should I rotate the flywheel keyway clockwise or counter clockwise from the crankshaft keyway?
4 How much should I rotate the flywheel? IE If Flywheel & crankshaft keyways line up at 12 oclock, should my first movement of the flywheel be to 1 oclock, 2 oclock, 11’30 oclock??
To Crosbyman – I have adjusted the cam & follower as you suggested. Some minor improvements to starting. Cold start 3 pulls at about 5/8 throttle with choke. Warm start no choke, 1 pull at about 1/2 – 5/8 throttle. Thanks. I think we are at the limit to what carb & fuel adjustments will do, that’s why I’m exploring timing as an issue. Another rabbit! I’ve given up on the reed valve theory.
thanks in advance, TomDecember 9, 2020 at 12:09 am #224687Hi Billw,
I think I missed your question. Cold compression is 98 PSI top & bottom cylinders.December 9, 2020 at 6:07 am #224688OK, your first picture shows the point timing advanced….
But, there are two timing issues to be considered. The point timing for sure is one, but the positioning of the mag plate at the time of spark is another. And unfortunately, on these small engines, there is no timing “grid” on the flywheel or corresponding mark on the block to compare it to. So, the point timing could be perfect, right in the middle of the hash marks, but the actual ignition timing could be retarded/advanced. Think about adjustments on an older car with points. There are two adjustments to check, the “point dwell”, and the ignition timing/advance. Forgive me for using the word “dwell”, this term has stirred up controversy in the past. Nonetheless, the point dwell could be set perfectly, but the ignition timing might still be way out of whack.
I want to be sure I understand what you are saying….Are you saying that the engine has been running with a properly positioned/unsheared flywheel key during your tests, and these altered keys are something you just tried now? What looks to be a very small change in that purposely altered key is amplified by the diameter of the flywheel, probably about a ten degree difference in timing out at the outer diameter of the flywheel.
Have you tried running the engine with the key altered in both directions/ advanced and retarded? If so, was there any noticeable difference in running qualities. I realize you can not run it at WOT in a barrel so full throttle performance can not be evaluated very well. My theory about timing was triggered by your running symptoms description. Retarded ignition timing will surely cause hard starting and explain why you must advance the throttle so far when starting. Retarded timing will also cause a poor idle and having to open that needle valve out to 2.5 turns. The final symptom that got me on this track was that you felt that the engine was not developing full power, and stumbled/popped during acceleration.
OK, forgive my covid brain, lately I seem to be stumbling over the simplest of calculations etc. So, let’s just say you are looking at the crankshaft/key with the flywheel off from the front of the engine….The key offset should face to your right/port side of the engine to advance the timing. Please feel free to correct me if I’m getting this wrong, wish I had some way of posting pictures/diagrams..
Like I say, I am having similar running symptoms with a 6hp using the conventional/unaltered universal mag. Doesn’t start real well, not a great idle, stumbles on acceleration, and lacks WOT power. Maybe we will both figure out something here….
OK, just reread your last post…The key was properly positioned for most of your tests, this is just something you tried now. Sorry I can’t really comment on your second picture, will just cause more confusion….Again, you have tried to offset key in both directions?? If so, you haven’t seen much difference in idle/acceleration quality??
I wish you had a conventional mag plate to install and try, which would rule our timing theory in or out…. -
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