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Intermitten Rough Idle Only When In Gear??? Ideas?

[Question] 
4K views 21 replies 9 participants last post by  twinDRAGZ 
#1 ·
So this weekend I encountered a new issue that I haven't ever had before. My left motor intermittenly did not want to hold an idle when it was in gear. I would shift it into gear and unless I applied some throttle it would die out and the motor would quit. No trobules restarting, no troubles running with just a slight amount of throttle applied and it ran GREAT all weekend. At RPM there was not a hick-up, nothing and the minute it would be shifted into nuetal it would idle perfectly. I was thinking maybe just the idle needs to be adjusted up but thought I would see what feedback I could find on here.

I pulled the plugs out and they were fairly dirty so I replaced them with new ones and that did not fix the issue. It just a few times did not want to idle when it was in gear again unless a tad of throttle was applied.

Any ideas anyone?
 
#2 ·
I have not encountered this exact problem, but I have heard that worn reeds can cause idle symptoms you are talking about. What I have had happen was several broken reed petals, which caused my motors to not want to idle at all - in or out of gear. The engines were hard starting and it was hard to even keep the engines running at low rpm/going into gear. PM Boatmaster (Drew), he might have a better idea of what's going on with your motor.......
 
#6 ·
What RPM does it idle at in gear? In neutral? Were the exhaust outlets underwater or trimmed out of the water when it was chugging and dying?
When shifted into gear it looses a few hundred revs and is maybe dropping down to around the 900 range and then falling from there until it stalls. When in neutral it is idling at approx 1200 rpms absolutly perfectly. And the motors were trimmed out pretty well and the exhaust ports were sitting atop the water. When trimmed in there was no change.
 
#8 ·
Idle Speed Adj

Is there a simple way to raise the idle on the motor? I am thinking that if there is a way to adjust it I will give that a try this weekend. I was going through my records last night and when the motors were rebuilt they had new reeds installed in it and I am wanting to try anything somewhat simple before I drag it back into town to have it looked at. Thanks!
 
#12 ·
You basically just want to advance the pickup timing. That is the screw on the throttle arm near the middle, that holds the top portion of the arm while the throttle is closed. Screwing it in will advance the timing at idle and raise the idle.
Thanks Keith. I'll definitely give that a try next weekend when I'm out there and hopefully that fixes it. Appreciate it!!
 
#18 ·
Mine are rebuild with lower compression heads then the original drag motors and last service that was done compression was good and leak down was perfect. The motor has roughly 80 hours on it. I will try a few of these guy's suggestions and if that doesn't fix the issue then I will be bringing it home for a teardown. I've never had an idling issue with this boat/motors until this and the second I apply a tiny bit of throttle its all good. And at speed its perfect. So hopefully its not time for topend work cuz I would of course prefer to wait til the end of the season for that.
 
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