idle stop screw & sparkplug recommendation

[JT!]

my '71 Evinrude 50 might actually be ready for the water today. i was wondering how many turns out my idle stop screw should be at.

i have started it in my yard but am waiting for the water to fine tune it.

anyone know off-hand?

and is there an R-type sparkplug i can use? i was told there are better ones than stock that create less local radio interference?!

 

[Dhadley]

Re: idle stop screw & sparkplug recommendation

The idle stop screw should be about 1/2 way in / out. Whatever it takes to make the motor idle well. The QL77JC4s should work in that motor.

 

[tashasdaddy]

Re: idle stop screw & sparkplug recommendation

from soft seat, 5/8 turn out, and adjust from there.
50 1971 - 1975 CHAMPION L77JC4 or QL77JC4 gap .030 they QL indicates quiet, that is what you want.

 

[larky]

Re: idle stop screw & sparkplug recommendation

I think Dhadley is talking about the idle screw on the timing advance arm. and tashasdaddy is talking about the mixture screw behind the two round black plastic covers directly on the front of the carb. you should know the setting for both when you get it running in the water. My 71' 50ho may be a different set-up but my idle screw( on the timing advance arm) is almost as far in as it can go. I feel I have tried everything to get it to idle better with no luck. it runs great other wise. I only mention this so that if you find that it runs the best with that idle screw turn almost all the way in, then that may be just the way it is.

 

[jtexas]

Re: idle stop screw & sparkplug recommendation

if you run out of idle stop screw (if it's all the way in & needs to go in some more, or vice versa), you can adjust the cable length using that thumb-wheel (whaddaya call those black adjusting nut wheel-looking things with corrugated edges?). But be careful when you do that, it might require a couple other tweaks.

 

[Dhadley]

Re: idle stop screw & sparkplug recommendation

The idle stop screw being about in the middle is just a visual thing we use to determine if everything is as it should be. The idle stop screw should be about 1/2 way, the cam foller arm should be about 1/2 way, the shift linkage should be about verticle and the trunnion on the cables should be about in the middle.

If the idle stop screw is all the way in we start to look to see what else is out of place. If the sync-n-link is OK other than that we start to look for what's making the motor idle bad. Weak spark, sticking rings, carb issues, air leaks etc.

 

[larky]

Re: idle stop screw & sparkplug recommendation

I don't want to high jack this thread. when I get my outboard back together from the t-stat and water pump job I will start a new thread on the subject. the only thing on the list that you (Dhadley) mentioned that I did not check would be an air leak. compression is good, spark is good, did the link and sync according to the manual, new carb kit as soon as I bought the motor etc. now to check for an air leak I have been told on other two stroke motors to spray carb cleaner around the intake and if the idle increases then there is an air leak. let me know if this is the correct method on an outboard.

thanks

 

[JT!]

Re: idle stop screw(timing related)

Re: idle stop screw(timing related)

so far i can do this:

1. pump the bulb on gas line until (just a little) gas overflows from carbs
2. start the motor
3. motor runs for 3-4 secs, then stalls.

i haven't used the choke, or set the idle screw or throttle.

I only have the earmuffs on, and the engine doesnt have a hole for water to squirt from. To be safe i wanted to get it in the river before tuning further.

Being a selectric model, my main concern is I hope that neutral will work when I fire it up; and not fly out at WOT, even worse fly back onto trailer at WOT.

Will a selectric fire up if the engine is not 'ready' to be put in neutral (ie: no voltage applied to green) or can it only be ROPE started in gear?


**should i anchor myself to land or is that a good way to lose a transom?

dont tell me not to do it; you know i need to get 'er dun and test that boat and engine on the water, any experience tips appreciated.


Thanks, you guys are 100x more helpful than my local shops.

 

[iwombat]

Re: idle stop screw & sparkplug recommendation

If you can overflow the carbs your floats are mis-adjusted.

Fix that first and retry.

 

[larky]

Re: idle stop screw & sparkplug recommendation

I think the safest way to test your motor is leave the boat strapped to the trailer. just be sure you don't back down the ramp too far. go to the ramp when there is likely to be very few people there.

 

[ezeke]

Re: idle stop screw & sparkplug recommendation

Iwombat is correct as usual; you should only be able to fill the float bowls by pumping the primer bulb. The floats should then close the valves and stop the flow so it does not reach the carburetors.

If you can bypass the float valves, you will flood the engine repeatedly, plus it is dangerous.