Large Model Association Forum

Ok, I know they are not great engines but I have seen a few that look to run well. My engine will start no problem and transition up to about one third throttle and run steady, anything higher than that and it starts hunting. The carb trumpet gets quite wet with a mist coming out of it (that doesn't sound right to me!). I have tried leaning and richening the his speed needle without any joy. Does anyone have any ideas?

Steve

Check first every bolt on the thing is tight, and its gaskets are doing their job, then turn to the carb, remove the diaphram plate, remove the rubber diaphram, is there any crud there? Is diaphram in good order? Flush the carb out in petrol, could be a simple blocked jet? Reasemble and try again,

Thanks Alan, I'll give that a go and see how I get on.

In trying to remove the carb to clean it, I manage to brake the pressure nipple and cannot find a replacement, been trawling the net for a couple of hours now. Also need a replacement gasket to go between the carb and the engine. It looks like there was two thin gaskets with a thicker spacer, need the whole thing as the previous owner had them stuck on with some kind of hard sealer.

Strewth, thats not good, take a fine philips screw driver, gently tap it a few times, until tge screwdriver forms is star shape on the errant nipple stud, exert pressure, and try to unscrew it, and be more carefull! If your struggling, send me the carb,

Many thanks once again Alan for your reply, it was the plastic elbow that snapped. I have managed to remove the brass insert, it was a push fit and not threaded but can't find anyone who stocks a spare. Would you be able to do anything with it? If so PM me your details and I will send it to you, thanks for the offer.

No idea unless i look at it, possibly be easier if you take the carb to a lawn mower service shop, they might have spares

Tried that today, unfortunately they were unable to help.

Hi Steve. Walbro fuel inlet elbows available here, with phone number.

http://www.rowenacarbs.co.uk/

Another very useful forum thread on the subject.
Tony.

https://www.rcgroups.com/forums/showthr ... ise-please

Thanks Tony, the brass insert on the fuel inlet looks longer in the picture than the pressure nipple I took out. I will give them a bell tomorrow and see what they say.

I have a replacement top plate on it's way from Rowena Carbs. Thanks again Tony.

Just hope I can get the engine running properly when it arrives!

Great find by Tony, use the time wisely, check the remainig bits of your carrb out, as we have talked about, google your carb make and number, might even find an exploded view

If you care to study this lot I think it will help you no end.

http://www.wind-drifter.com/technical/wg8walbro.php

https://www.helifreak.com/showthread.php?t=326599

http://www.walbro.com/wp-content/upload ... series.pdf

http://www.footflyer.com/fix/motor/carb ... walbro.htm

http://www.footflyer.com/fix/motor/carb ... walbro.htm
Good luck.

Tony

And finally if you want to make your own metering lever gauge tool follow this link:-

http://www.wind-drifter.com/technical/WalbroGage.pdf

Carb stripped down, cleaned and reassembled. Everything is tight, got fresh fuel and still hunting. Click on link to see, any help would be much appreciated. https://vimeo.com/228552057

Shot in the dark here Steve. If you have a spare ignition module or can borrow one from another model swap it over.
Also try a different ignition battery. A battery checker doesn't always tell you the whole story. Our chairman can vouch for that. If no difference then we will have to dig a little deeper into your carb.
Tony.

Listening to your video, that sounds like an ignition miss.

Do you have the original Chinese plug in it?
If so swap it for a NGK, Champion, Bosch etc.
Is the spark plug cap pushed onto the plug all the way..high tension lead in good order?
Try another ignition module.
Pick up sensors have been known to go wonky, see if you can borrow one and try it.
As far as the carb goes, you say you have played with the high speed needle. The high needle does not come into play until about 3/4 throttle so have you tried adjusting the low needle, (although it seems to idle and transition well...to a point)
Have you tried plugging the ignition module directly to the battery, by passing the kill switch?

Just some of the things I have tried over the years. More recently I have had a few pick up sensors that have given grief.

Good luck.
Cheers,
Dave.

Tony/Dave, Thanks for your replies.
It's a new battery so "should" be OK but I will try another one. Was hoping not to have to buy another ignition module.
It is still the original plug, will get a replacement NGK/Champion tomorrow. All leads in good order, bought the engine second hand and it looks as though it has hardly run (now I see why!).

Are the sensors specific to the ignition or will any one do. Am I correct in saying that if I try say an RCEXL ignition that I need to change the timing? Can the Hub be rotated so that the magnet is in the right place?

I will try to change what I can and see how I get on.

Thanks again guys
Cheers
Steve

Steve , whatever ignition module you use couple it with the sensor that came with it then you cant be wrong.
Most sensors are set around 28 to 30 degrees Before Top Dead Centre but if you just fit it centrally for the test, the engine should run well enough to see if the fault has gone.
Good luck and come back if the fault is still there.
Tony.

PS. Hi Dave, Regards and hope Canada is treating you well.