Home › Forum › Ask A Member › Johnson TD-20: Looking for some input…
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Brent Bergen.
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March 25, 2016 at 4:07 am #33878
Thanks very much for the replies and links! I removed the intake/exhaust manifold to clean and reseal it. I just received the "Mercruiser retrofit" style float. I plan on ordering those leather washers from Mr.Lautner if possible. I will plan on going through the carb completely and clean the entire fuel system for starters. I am aware that carb cleaner isn’t a very 2 stroke engine friendly fuel and it is not my usual practice to use it. Hopefully next time it fires, I can burn some 16:1 in a water tank… I’ll probably have a couple questions once I get into the carb, has been a little hectic lately and haven’t had much extra time to work on it. Thanks again for the help.
April 2, 2016 at 7:46 pm #34218In regards to using the modified Sierra or Mercury float: Which way should I install this float? (One side is flat, the other tapered with a spring in it)
I’m assuming it probably doesn’t matter and will more than likely install the flat part up and drill a hole there for the clip screw. Remove spring portion and ream out center with a slightly larger drill bit. Sound ok?April 2, 2016 at 8:10 pm #34219I put them in the TN’s with the flat side down. The spring will pull out so you can drill the plastic core to fit your needle. If the core comes out, a bit of crazee glue will hold it in place.
April 2, 2016 at 10:56 pm #34230quote Mumbles:I put them in the TN’s with the flat side down. The spring will pull out so you can drill the plastic core to fit your needle. If the core comes out, a bit of crazee glue will hold it in place.Thanks!
April 3, 2016 at 12:54 am #34234I used a number drill, can’t remember which size, as this allowed the needle to be a snug fit in the Merc float. No retainer clip needed as the float is a friction fit on the needle and the fuel level can be adjusted quite easily by sliding it up or down on the needle.
April 4, 2016 at 3:39 am #34299Thanks again Mumbles. I ended up using a drill bit that was about the same diameter as the needle and "honing" it out a bit over that for a tight fit. I did use the original retainer clip and brass screw in the foam float. I bent the clip in a vice to compensate for the taper of the "retrofit" float. Float seems to be working just fine, had the old TD running off the carb for the first time today in probably many years. I’m not confident float height is where it should be but it seems alright? Yesterday I soaked the lower half of the carb in Pine-Sol (have had good luck using in the past) followed by hot water, solvent, and compressed air through passages. The old unit sounds pretty good but I definitely need to read up on adjustment and settings. I could not get it to run well on low speed and high speed without considerably changing adjustments. The primer does work but it does leak. Have an envelope here with Mr. Lautner’s name on it…
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April 4, 2016 at 11:33 am #34311With the original cork floats, the top of the float should be even with the groove in the brass float needle. The retainer clip fits into the groove and the tiny brass wood screw then keeps it in place at the correct level.
I’m not sure about the retrofit Merc floats, but I would think it should be at the same height?
Improvise-Adapt-Overcome
April 4, 2016 at 11:14 pm #34347quote aquasonic:With the original cork floats, the top of the float should be even with the groove in the brass float needle. The retainer clip fits into the groove and the tiny brass wood screw then keeps it in place at the correct level.I’m not sure about the retrofit Merc floats, but I would think it should be at the same height?
I think I’m good there. The Merc float was close to the same height as the original cork float including the little plastic piece sticking out that retained the spring. (although it was a little shrunken and distorted). I have the original retaining clip tight up against that plastic nipple holding the needle in the original detent. The float/needle seem to be working fine. I think I snapped a quick pic if it would help anyone in the future, I can probably post.
Anyone happen to know any carb adjustment starting points? Spark seems good but I have not yet adjusted points and should probably do so when I get a chance. I assume the float leaking when depressed probably won’t affect "tuning" much?
April 5, 2016 at 12:14 am #34352For carb adjustment starting points, try 3/4 turn open from gently seated on the high speed knob, and 5/8 to 3/4 turn open on the low speed needle.
Improvise-Adapt-Overcome
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