Help me get this thing to idle!!!

[destroyer85golf]

Got my speeditwin all out back together. Set the points at .012 and it fires up, but as for idling down, it doesn’t want to do that without backfiring. Any help???

https://youtu.be/JkdnhxLTUY4

Sorry about the video , brother decided to turn the camera sideways 3 seconds in.

[Tom]

Check the carburetor for a clogged passage. Also, the crankcase to cylinder gaskets and the carburetor gasket.

T

[destroyer85golf]

So, I cleaned the carburetor again. It has great fuel flow. I ran gas out into a container to look at it. The cylinder to crankcase gaskets seem to be good. The carb gasket is about the consistency of hard brittle plastic. So I put a thin coat of RTV on both sides . To get it to start I ha e to screw the low speed jet in. then once it starts, run it out till it smooths out. Along with retarding the timing a bit. This is my first motor where I have to control the timing and all the other things! It’s amazing how far motors have come! Thank god for throttle and timing linkages!!! Anyway I got it to run, but it’s pretty finicky. I have a feeling I’m still not doing it correctly .

[The Boat House]

• This reply was modified 5 years, 5 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[david-bartlett]

Tubs,

Great answer. I ran my PO15 yesterday on a boat for the first time and can really relate to this. Sure could use another hand. I was thinking at the time how glad I was to have two good hands.

As for the SpeediTwin issue it does sound like is running lean.

quote Tubs:

quote destroyer85golf:

Thank god for throttle and timing linkages!!!

I have a feeling I’m still not doing it correctly .

You have missed the point of running these things.
It’s not brain surgery but they require some skill,
knowledge, and experience. As you have learned
not just anybody can run one. It’s no different than
a cell phone. If you’re not interested in learning how
to use it you never will. All that is required is to use
one hand to steer, one hand to adjust the carburetor,
and one hand to adjust the timing. Simple!!! Learning
new things has its rewards. When it backfires like that
its usually indicates that its lean (too much air not
enough fuel) for some reason.

[destroyer85golf]

Later on I went back after talking on Facebook to a few people. You guys are 100 percent correct, I backed out the low speed adjustment out while it was running, and it cleared up. You definitely need three hands, as you guys have said . It’s also gonna take some practice to get it all down . The one thing that stuck out was the pressure of the discharge water came out. Good lord it was like a full bore garden hose!!

[Anonymous]

The points clearance should be .020 not .012 You need to set the fast speed mixture at WOT first(with the timing advanced to the point that the boat goes no faster) , then slow the motor to idling speed and with the timing backed off and then adjust the idle mixture in that order.

[george-emmanuel]

[quotthen slow the motor to idling speed and with the timing backed off and then adjust the idle mixture in that order.e][/quote] Is great advice! Speeditwins do not like advanced throttle with timing retarded, at all!

George

[Anonymous]

First off, 6039 speeditwin aren’t good motors to test tank.
Set the points to .020, and take it to the lake.
Set high speed first, then slow it down to dial in idle, but don’t expect a speeditwin to be a slow troller.

You will want to run it with the front cover on, unless you want to get sprayed with a fine mist of gas.

Someone has posted the owners manual, somewhere, because I printed it off one time.
Read it a few times, and you can develop your own best method. The 6039s are a motor to be operated, not simply "run"

I have ran 3 diffrent 6039 speeditwins, and all of them run slightly different.
Some faster, start easier, idle better, etc.
Mark

[outbdnut2]

quote destroyer85golf:

. The one thing that stuck out was the pressure of the discharge water came out. Good lord it was like a full bore garden hose!!

That water discharge is all the cooling water, not just a telltail stream to tell you there is water circulating like most newer motors have. There is no thermostat so it pumps like that all the time. This is on all 1955-1958 Johnsons/Evinrudes from 5-1/5 to 35 HP, except the 1958 Lark and Super Sea Horse 35s that have thermostats.

Note the high speed carb jet is very touchy on your model – a half a number difference on the dial can make it run lousy – and like the others said – set this at max throttle on a boat.
Dave

[Author]

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