Microlighters

Can one decoke chemically too often? I did my first one yesterday and saw loads of gunk pour out. Must I not decoke till no gunk pours out? Needless to say motor seems more responsive

DieselFan wrote:Can one decoke chemically too often? I did my first one yesterday and saw loads of gunk pour out. Must I not decoke till no gunk pours out? Needless to say motor seems more responsive

Hi DF, What is a decoke chemically "I did my first one yesterday and saw loads of gunk pour out."

DF....the chemical stuff only works up to a point. The hard stuff doesn't come out/off. Your best bet is to strip it down and de-coke manually.

Hey Duck, I've heard from a few guys saying they did and always will chem decoke every 50-100 hours and at 700 hours no probs even same crank? One opened up at 500 and said looks like new. This was with premix and injector.

Excuse my ignorance but is this not a bit like the oil on filters thing? Most the parties in that thread have loads of hours on rotaxs and are treated with respect (you being one) and yet the views were polar? Hence why I ask can't the hard stuff come off if I chem decoke every 25 hours etc? with a plug change. Admitably the advice I was given was different to the steps on the can, so might have been "perfected" over time

Cobra, Chem decoke is the debate not long ago here about the Carb and head cleaners that you buy instead of manual decoke.

Hi DF

I read the other threads/postings and all agree a manual decoke is better, around 400-500 hours, agreed and I think it is obvious that the inspection and cleaning should be done by opening the engine with an overhaul.

I think your question is , and I would also like some comments on,

* is there any harm in using the product every 25 hours especially if 400-500 is only in a year or two - at least you have some peace of mind

* could it cause any damage to the rotax engine or possible loss in performance in time

* is it a waist of money doesn`t seem that other use these products and rather wait to the overhaul.

DF, what product did you use - Quicksilver Power Tune

Sorry guys, I have never used this stuff on a regular basis (as in every 25 hours) and I don't know what it's made of/from. Can't comment.
I'm pretty much from the "old school' and prefer to do things like it has always been done (the hard way, then I know its done right)

Hi DF, I chemically decoke every 50-100 hr's on my engines and have never had a probl. It helps keep the rings from sticking. To test yourself, do a compression test before and after. You will note the difference. On my 503 the compression after 500hr's is still pretty much the same as a new engine. If I remember correctly it's around 115psi.

KFA, when last have you stripped that motor? My guess is you gonna find carbon build-up on top of the piston regardless.
Maybe it does help to keep the rings from sticking. I can't comment.

What products are available for chemical decoke, and how is it done?

Duck, I check the piston via exhaust after every decoke and find little to none deposits still on the pistons. If I do find I just repeat the process. Works like a charm but I agree that at 500 - 600 hr's the motor must be opened and the crank checked. I don't believe it is nessecary at 300hr's. An engine is like a 2 liter of coke, once opened it always goes flat. That is why I believe that if all the external checks like compression, CHT, EGT and so on are correct there is no reason to tamper with an engine. But that's just my opinion.

Ok so as Tjoek said. What products are available or adivisable and how is it done?

Go to the local auto spares shop. Goes under the name of Carb cleaner.

Wynns
Panjaard
Loads of brands, around R20 a can. Litts by far the cheapest around 5-10 cheaper than AutoZone, but Autozone was closer for me.

Was told to

1. Spray about 1/4 into each carb once engine is warm around 3000rpm, in bursts.
2. Take off spark plugs, spray 1/4 of the remaining 1/2 into each.
2. Wait 10-20 mins - you'll see loads of crap pouring out ofcourse your air filters are off.
3. Start it up again and get it warm, do 1 to 2 30 secs burn on max rpm to get gunk out, obviously in a cooled area etc.
4. Change plugs.

I didn't follow this exact as I first put it into the carbs bowls as the can said, but was told otherwise thereafter. I also gave the filters a good clean.

The products I use is Wynn's Compression stabilizor@ R 27 each and Combustion chamber cleaner available @ Midas @ R27.63 I use one of each every time I decoke

I know that Big G and Ratman in their 2 stroke days swore by:

Quicksilver Powertune - Available from boat shops

Advice I got from Big G was to do chemical decoke every 50 hours, and this apparantly really does make the engine run better and last longer

PS: Darkhelmet, I finally found us a can!!! Boatshops have stock again

D