stuartasutherland Posted August 13, 2012 Share Posted August 13, 2012 Bad times. I was running at a nice pale coffee colour on the plug and on Friday night the engine sometimes would cut to tick over and struggle to get up the revs again. Looking back, I should have landed and probably could have saved myself some coin. So, just in case I'm missing anything, other than too lean, what else should I consider? Check the carb for dirt? ps it is a Parajet Volution 1 Thanks Quote Link to comment Share on other sites More sharing options...
pete_b Posted August 13, 2012 Share Posted August 13, 2012 Was the O ring seal ok? Looks like its been blowing on the bottom in the picture. Pete Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 13, 2012 Author Share Posted August 13, 2012 Hi Pete, Ive been having problems sealing the head gasket. There was an oil leak out two sides, but not serious amounts. I replace the o ring pretty often as it keeps leaking and destroying the seal. I have ordered a new head in case mine is warped. Is it possible to use a gasket sealant as well? Quote Link to comment Share on other sites More sharing options...
pete_b Posted August 13, 2012 Share Posted August 13, 2012 Yes but only a small thin layer. Get a thickish piece of glass and some 1200 wet and dry, hold a full sheet (or stick it around the edges with tape) on to the glass then put your head on it and very gently start moving it in small circles you can add some water with washing up liquid as you are doing this. After a couple of minutes wipe the face of the head off and if it is not nice and clean ALL over then the head is not true. You can carry on doing this until the head is true. Pete Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 13, 2012 Author Share Posted August 13, 2012 Thanks Pete, I'll get on to it. Quote Link to comment Share on other sites More sharing options...
enzo200500 Posted August 13, 2012 Share Posted August 13, 2012 Check that pesky little round gauze filter in the carb Stu! sorry to hear about the engine. Quote Link to comment Share on other sites More sharing options...
thyslouw Posted August 13, 2012 Share Posted August 13, 2012 Hi Stuart I have rebuilt a couple of paramotor engines , first what type of motor is it ? if a Ros 125 it could be the decompression valve , oring or dirt is carb on the pump side ( look if little filter inside carb is blocked ) If the pop off pressure is to high the motor can run to lean , it can also be a leaking base gasket or one of your crank seals can be leaking , how many hours on the motor and type ? all the best Thys . Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 13, 2012 Author Share Posted August 13, 2012 Hi Thys, it is a Parajet Volution 1 (180cc) with 200+ hours. Thanks for the ideas. Quote Link to comment Share on other sites More sharing options...
thyslouw Posted August 13, 2012 Share Posted August 13, 2012 Hi Stuart 200 hours I would defnitaly replace the crank seals and main bearings , that will force you to replace the bottom gasket , not a expensive exercise about 50-60 £ if you do it yourself , I went thru the same with a Blackdevil a couple of years ago it was the crank seals , just make sure you use Viton seals they can stand the heat , you get it from your local bearing suppliers . There is not much to a 2 stroke engine if your seals and bearings is fine it could go for thousands of hours . Most of outboard engine seizures is caused by crank seals . You just need a small press . Quote Link to comment Share on other sites More sharing options...
Guest Posted August 13, 2012 Share Posted August 13, 2012 Hummmm,,, I am not so sure about this. 200 hours, for a full strip down a re-build is a little OTT.... My V1 compact hit just over 1000 hours of School use before the bottom end needed looking at. SW Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 13, 2012 Author Share Posted August 13, 2012 Hi Stuart 200 hours I would defnitaly replace the crank seals and main bearings , that will force you to replace the bottom gasket , not a expensive exercise about 50-60 £ if you do it yourself , I went thru the same with a Blackdevil a couple of years ago it was the crank seals , just make sure you use Viton seals they can stand the heat , you get it from your local bearing suppliers . There is not much to a 2 stroke engine if your seals and bearings is fine it could go for thousands of hours . Most of outboard engine seizures is caused by crank seals . You just need a small press . Hey Thus, the engine had a strip down last year where the bearings were checked and seals replaced. All gaskets too. Just cleaned it all up and the cylinder has a slight scuffing, hope I can get away with that one! Carb is all clean, fuel lines okay, reed valve seems fine. Could it be Pre ignition? Quote Link to comment Share on other sites More sharing options...
Neilzy Posted August 13, 2012 Share Posted August 13, 2012 Check the pop off pressure!!!! Quote Link to comment Share on other sites More sharing options...
stuartasutherland Posted August 14, 2012 Author Share Posted August 14, 2012 It's a new carb about 2 months ago. I have no idea how to check / adjust the pop off pressure. Just assumed it was fine seeing as it hasn't changed since i got it. Quote Link to comment Share on other sites More sharing options...
thyslouw Posted August 15, 2012 Share Posted August 15, 2012 Hi Stuart here is a link how to check your pop off pressure http://www.aerocorsair.com/id28.htm you can go to a chain saw shop or ask around for a pop off gauge , I made mine myself but it better to use one than to built one or buy one because it is expensive . I have other links if this one don't help . The pop off on my PXP Menari 180 is 16 psi and it reseat value 11 . The reseat value is important if it is to low your carb will flood , your carb operates between 7 and 8 psi so ideal your reseat value should be a minimum of 10 psi . You can ask your manufacturer of the motor what the pop off should be , or google it . If the bottom part of your engine is fine it can only be , pop off , leaking head gasket , or your head bolts was loose I check mine frequently and sometimes it need some tightening , or somehow someone turned your high screw . You say that the carb is 2 months old did you tune it with the motor running on your back ? if not this might also be part of the problem , all the best , Thys . Quote Link to comment Share on other sites More sharing options...
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