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Pap decompressor problem?


cambodia
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I am not the resident mechnic here but, that looks a little excessive to me?

Someone with the actual answer will post soon I am sure.

I would not have been happy if my motor did this from new, (or even now for that matter)

SW :D

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I have a PAP with the Ros 125. I get regular staining of the prop from oil deposits eminating from the exhaust.....................but nothing as bad as that?

The fouling oil is simply wiped off with WD40.

The engine has 12 hours and I mix the fuel as per PAPs recomendation.

Yours does seem wildly excessive.......fuel oil mixed correctly?

Mike

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I am still running in with a higher oil to petrol ratio.

Could I be wrong and this is from the exhaust?

Most of it looks like its coming from the decompresser as its on the barrel as in picture one above,

and the it is too near the centre of the prop to be from the exhaust.

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Like every body else whos replied to this post your Decompessor is not sealing properly..Take it out and give it a clean..also your oil/fuel mix looks oil rich........while you are at it check your spark plug is not fouled up due to the excess oil ......unless you want to practice you emergency landings

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From the pictures you have 2 leakages here. As you say the decompressor is letting oil residue pass and this is the lighter residue on the barrel fins and also closer to the center of the prop. This is also very common on pull start black devils. Pull out the decompressor and leave it soaking in WD40 until it starts operating properly again. If the decompressor keeps getting bunged up the replace it with a blank (a bolt or similar). The Ros (it's not a Ross by the way) didn't have a decompressor until a year ago and works fine without it. The second issue you have is a thicker, stickier gloop coming out from the junction of the cylinder exhaust port where the exhaust manifold mates. Some high temp sealant (such as Yamabond or Hondabond HT) will sort this.

What fuel:oil ratio are you using? PAP say 40:1 but you'll find yourself with coked up internals if you run this for long. Everyone else uses 50:1. Hhmmmnnn, now if you ran at 40:1 you would be less likely to cause a warranty return yet the problems of running too much oil wouldn't manifest until after the warranty expires... cynical, moi!

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Hi Fanman

PAP now say 33/1 mix for the first 6 hours and like a good boy this is what I am doing.

I will go 40/1 and see what happens.

No wonder all this excess oil is trying to escape and the decomp is forever bunged up! Must be costing you a fortune in synthetic. Running too much oil in the mix (a bit extra for mum) is not necessarily a good idea, a concept that PAP don't seem to get.

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I have also had decompressor problems with my Pap. Slightly different to yours in that the plastic button on the end comes off. I've had three new decompressors and they have all done the same. I've reported this problem to skydragons.

I have considered that it might be my engine running hot but I have checked the oil ratio and plug to ensure it is not running lean everything looks OK, it seems to be operating in the normal temperature range.

Any one else had this happen to them?

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Hi Fanman

PAP now say 33/1 mix for the first 6 hours and like a good boy this is what I am doing.

I will go 40/1 and see what happens.

No wonder all this excess oil is trying to escape and the decomp is forever bunged up! Must be costing you a fortune in synthetic. Running too much oil in the mix (a bit extra for mum) is not necessarily a good idea, a concept that PAP don't seem to get.

Just spotted this post and I have a very similar problem on my Rad Arrow.

I also run at 33/1 as per the recommendations. It's stated in the manual and a sticker on the machine itself. What would be the repercussions of running at 40/1 or should I stick with the mans. recs.?

I'll take the decompression valve out and see if I can get it to seal properly!

Cheers

Mark

:propbreak:

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Here's another thing... TTS (or Power 1 TTS as it is called these days) is a very good oil for lubricating but it does leave behind much more residues than other 2 stroke oils. Many people in the US won't touch TTS for this reason and go for oils like Yamalube 2S instead. I use an engine that is also put in PAP frames with TTS but when I tried running it at the PAP recommended post-run in mix ratio of 50:1 I gummed up my piston ring in less than 5 hours to the point where it stuck. I went to 60:1 and it was still sooting up so now run 65:1 which is the engine manufacturers (not PAP's) recommendation. In fact the engine manufacturer runs his own engine at higher ratios than that!

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Alarm bells ......to me anyway......melting plastic decompressor it shouldnt happen sounds like just what happened to my mates. when his engine was running super hot ....and the reason....SIMPLES .....check your timing I reckon its slipped especialy if youve had it pull back on you when starting....the crank has no woodruff key and the flywheel is tightened in position by the tighness of the nut only ...... :shock:

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