Capotec2015 Posted March 30, 2017 Share Posted March 30, 2017 Hi, I am looking for some advice please. I noticed little black streaks on the prop and can see seepage from the exhaust and also it appears to be coming from possibly the compression valve too. So, I had the inner O rings replaced and high temp gasket sealant applied -however, it looks like its coming from the joint before the exhaust meets the barrel. Is this a new exhaust situation or is there any other sealant that would cure this. If its a new exhaust then fair enough. Here's a link to a picture of it. https://www.dropbox.com/s/sfn6ow8venorjf5/IMG_0580.JPG?dl=0 We put some PTFE tape on the compression valve but I think the valve itself may be faulty as there is still a leak. I am going to buy a new one from the supplier in Italy... So, any advice welcome - thanks Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted March 30, 2017 Share Posted March 30, 2017 Had similar issue on my Miniplane initially, but they recommended a concial copper washer between the exhaust and cylinder exhaust mount to solve the issue. Worked fine. I think the Miniplane washer is a custom one designed for Miniplane only though. gd Quote Link to comment Share on other sites More sharing options...
kiwi k Posted March 30, 2017 Share Posted March 30, 2017 What % premix you using and how many hours on engine ? Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted March 30, 2017 Author Share Posted March 30, 2017 HI -Thanks for responding. premix is 125ml to every 5L -I took that from the ROS motor user manual. Here is a link to the exploded view of the entire engine -https://www.dropbox.com/s/9q56h3d8osdh35b/ROS MOTOR CATALOGUE.pdf?dl=0 The leak appears to be coming from between part number 98 and the main body of the exhaust. I am wondering if something could be done to stem the oil or maybe part 98 needs to be purchased -not sure... I dont know how many hours the engine has done. It was a used engine when I got it. I have never flown it as I am just learning. It has probably done 2 hours total running time with me. It has tons of compression and starts relatively easily (using decomp valve) after a few pulls from cold and usually one pull from warm. Although you do need to give it a good pull - half assed pulls will simply not start this motor....that said, I have never not been able to start it. I am just getting used to having it on my back and now looking to see if I can fit a kick start to it as I am looking to be able to start it in the air -when I finally get there... I have some experience with 2 strokes as I used to work in forestry with chainsaws and rode 2 stroke bikes in my youth... Thanks Paul Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted March 30, 2017 Author Share Posted March 30, 2017 Update - --Took the exhaust off and I popped the springs off of the joint (part 98 in the catalogue link above)that is between the main exhaust body and the barrel/head - - and it literally fell out. You can see how black with oil it is here -https://www.dropbox.com/s/v1yvpvjnsm6ga7y/IMG_0581.JPG?dl=0 Does anyone know if it should be loose like that -are the springs there just in case it breaks and goes into the prop? So I dont know if: a.Its a worn part and needs replaced. b. Needs cleaned and high temp gasket sealant applied and re-fitted. Again, any advice welcome, Thanks Paul Quote Link to comment Share on other sites More sharing options...
kiwi k Posted March 30, 2017 Share Posted March 30, 2017 6 hours ago, Capotec2015 said: https://www.dropbox.com/s/9q56h3d8osdh35b/ROS MOTOR CATALOGUE.pdf?dl=0 Thanks Paul Paul in the manual page 5 picture of exhaust, when you zoom in to me it looks like a standard ball and socket connection, but in you 1st post in your picture yours look's like is a straight pipe to spigot connection with a gasket, On original the gaskets look like they go head side and not exhaust side. But i have never had any experience with Ros engines, but most paramotor exhausts i thought we're ball and socket meaning no gasket needed just 2 or 3 retaining springs. So maybe your has been modified at sometime or maybe somebody who owns a Ros knows different ? Quote Link to comment Share on other sites More sharing options...
kiwi k Posted March 30, 2017 Share Posted March 30, 2017 plus 125ml would be 40:1 aqnd Ros manual says 2.5% so thats about right, but are you using mineral or synthetic ? Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted March 30, 2017 Author Share Posted March 30, 2017 HI Kiwi K -I think you're right... On the catalogue picture there is no gasket shown between part 98 and the main exhaust body. Looking at my actual one now I have taken it off, there is no evidence of one ever being there...the whole thing seemed to be able to swivel at that joint, which may be why its a ball and socket... So, trying to figure out whats going on with the leaking oil a. Part number 98 is worn somehow b. The exhaust connector opening is somehow stretched slightly c. The exhaust system is actually fine but something more internal is going on There is plenty of compression so piston rings seem to be ok from what I have read about the symptoms of bad rings - maybe its down to carburetor and mixture... Time to watch some carburetor videos..... Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted March 30, 2017 Author Share Posted March 30, 2017 Just saw your other question - the oil is Castrol Power 1 2T Fully Synthetic... Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted March 31, 2017 Author Share Posted March 31, 2017 New Update - after more research, this could simply be carbon build up on the walls of the expansion chamber - and the exhaust needs cleaned out -either by hot torch - or caustic soda. I dont have a torch so going down the caustic soda route.....will let you know how I get on.... Thanks Paul Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 7, 2017 Author Share Posted April 7, 2017 Nope. After caustic soda bath and degrease and reassembly, new spark plug correctly gapped, new petrol mix -high and low needles check for one full turn out - still getting oil leak... Thinking of replacing carb now - - Quote Link to comment Share on other sites More sharing options...
kiwi k Posted April 7, 2017 Share Posted April 7, 2017 Have you done a compression test with a gauge ? Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 7, 2017 Author Share Posted April 7, 2017 Not done a compression test -will look into that this evening. Dont have a gauge -will look to buy one and see how I do that and what the compression should be on this engine. Thanks. Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 7, 2017 Author Share Posted April 7, 2017 Compression tester ordered.. will research what its supposed to be and get back -and while Im at it I think I will become a paid member of paramotor club too ! Thanks Paul Quote Link to comment Share on other sites More sharing options...
kiwi k Posted April 7, 2017 Share Posted April 7, 2017 good should be about 135-140. Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 10, 2017 Author Share Posted April 10, 2017 Just wanted to check something, does the throttle have to be held while doing the compression test? Thanks. Quote Link to comment Share on other sites More sharing options...
AndyB Posted April 10, 2017 Share Posted April 10, 2017 1 hour ago, Capotec2015 said: Just wanted to check something, does the throttle have to be held while doing the compression test? Thanks. Hi, Nope. Holding throttle wide open will give an increase in compression. It is best to hold throttle open, although often the gauge will not notice the difference. Science: Throttle closed gives smallest air intake and hence causes suction (lower pressure) so less air gets in. Then the air that entered the cylinder is compressed somewhere in the ratio of about 8.5 to 1 and 10.5 to 1. Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 13, 2017 Author Share Posted April 13, 2017 First compression tester order got cancelled -second one arrived yesterday but I was away and couldnt do the test. Just tested it now. 5 pulls X 3 tests -topped out at 150 psi each time... Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 13, 2017 Author Share Posted April 13, 2017 Throttle held in and no throttle..results were the same... Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 13, 2017 Author Share Posted April 13, 2017 Cold engine... Quote Link to comment Share on other sites More sharing options...
AndyB Posted April 13, 2017 Share Posted April 13, 2017 That's not bad! 150/14.5 = 10.3 to 1. Doing it hot usually increases the reading as well (as the expanded piston rings form a slightly better seal). Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 13, 2017 Author Share Posted April 13, 2017 (edited) From the ROS manual on the web it shows as 10.6 to 1. http://www.rosmotor.it/manual web.pdf Doing it hot may have taken it to the target figures.... So, all good for compression then and not the likely cause of black oil leak? Thanks Paul. Edited April 13, 2017 by Capotec2015 Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 13, 2017 Author Share Posted April 13, 2017 Just wanted to say thanks to all that responded -I'm kind of not sure whats going on but will keep going till I get the bugger sorted!! Cheers!! Quote Link to comment Share on other sites More sharing options...
Capotec2015 Posted April 17, 2017 Author Share Posted April 17, 2017 OK -new angle on it. Its possible that the socket joint has been widened over the years and is no longer the snug fit it should be. Vibration etc. The oil may just be the natural by product of a 2 stroke engine but because the socket joint has been widened, the oil is getting out there. So, trying some gasket compound to see if that cures the leak..... Quote Link to comment Share on other sites More sharing options...
kiwi k Posted April 17, 2017 Share Posted April 17, 2017 1 hour ago, Capotec2015 said: trying some gasket compound to see if that cures the leak..... it's a ball socket for a reason and applying sealant or compound might work for a short period of time, but my next step would be replace socket area at least or complete exhaust. Quote Link to comment Share on other sites More sharing options...
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