Moster 185+ Idle dropping

[SWolf]

Engine has 12hr and having a issue with idle while flying. I come off throttle and it drops to 2800 then the normal 30ish seconds to drop down to around 2300-2400 but if i idle for 3+min it will want to drop down very low 1800 or less range at that point i pull more throttle to bring the idle back up any ideas?

[cas_whitmore]

On my walbro I had turn low end jet in a 1/8th ‘ or 10mins like on a clock 

Cas , 

[SWolf]

11 minutes ago, cas_whitmore said:

On my walbro I had turn low end jet in a 1/8th ‘ or 10mins like on a clock 

Cas , 

so a tad richer turning CW? I think i am already on the rich side

[cas_whitmore]

Might have to balance the two ‘ but normally if it’s hanging on the revs on the way down to idle it’s or I have sorted with the low end ‘ out of interest has the butterfly got a small half moon recess where it shuts against the carb body ‘ throat ‘ 

[SWolf]

16 minutes ago, cas_whitmore said:

Might have to balance the two ‘ but normally if it’s hanging on the revs on the way down to idle it’s or I have sorted with the low end ‘ out of interest has the butterfly got a small half moon recess where it shuts against the carb body ‘ throat ‘ 

I have quite a while left on the warranty so can not play with the H screw for a while. 

[cas_whitmore]

Ok so throttle stop screw and low end jet to tinker with ‘ I haven’t had it on a walbro carb ,but I’ve had air being sucked past the threads of the jets on a tilletson carb , all worth a check . Or return it to dealer to sort .

cas .

[Hann__]

I think you may be expecting too much from a 2-stroke fitted with a simple - rather crude some would say - diaphragm carb in expecting it to idle consistently for extended periods. 2-strokes will tend to get rather cool and oil-up when running at idle for a while and will need a `blip` of throttle to help.

1800rpm isn`t so low it`s in danger of stopping but is in the range where the engine will probably be shaking somewhat - not good for comfort, engine mountings or exhaust life, especially if it`s noticeably `four stroking` -  a sign that it`s running rich.

What are you doing that requires 3 minutes of idling whilst flying a PPG - thermalling?

Although it`s possible to fine-tune the carb to get the idle reliability you are after it`s going to take some tweaking which may not be available to you in the warranty period.

Generally a rich mixture will lower the idle speed and leaning out will increase - screw in to lean out to richen.

If you can adjust the low screw in the warranty period screw it in a smidgeon - not too much to affect throttle response off idle though - i found the factory settings to be on the safe side, ie: very rich.

 

Edited August 27, 2018 by Hann__

[SWolf]

23 hours ago, Hann__ said:

I think you may be expecting too much from a 2-stroke fitted with a simple - rather crude some would say - diaphragm carb in expecting it to idle consistently for extended periods. 2-strokes will tend to get rather cool and oil-up when running at idle for a while and will need a `blip` of throttle to help.

1800rpm isn`t so low it`s in danger of stopping but is in the range where the engine will probably be shaking somewhat - not good for comfort, engine mountings or exhaust life, especially if it`s noticeably `four stroking` -  a sign that it`s running rich.

What are you doing that requires 3 minutes of idling whilst flying a PPG - thermalling?

Although it`s possible to fine-tune the carb to get the idle reliability you are after it`s going to take some tweaking which may not be available to you in the warranty period.

Generally a rich mixture will lower the idle speed and leaning out will increase - screw in to lean out to richen.

If you can adjust the low screw in the warranty period screw it in a smidgeon - not too much to affect throttle response off idle though - i found the factory settings to be on the safe side, ie: very rich.

 

It dose seem the factory has it set on the rich side. Good thing spark plugs are cheep