wallboy Posted June 18, 2014 Share Posted June 18, 2014 I have a Simonini Mini 2 which starts and idles fine but wont rev over half throttle. Have cleaned the carb with air compressor, fitted new gaskets etc, have also tried using another carb off a working motor and still no good. There is lots of black oil/fuel coming out of exhaust flange but the spark plug is clean and dry My mate thinks it could be crank seals, ideas anyone? Quote Link to comment Share on other sites More sharing options...
Guest Posted June 19, 2014 Share Posted June 19, 2014 If it is coming from the crank gasket, you should be able to find the source to confirm it. I would get some de gunker all over it, give it a good scrub so you have removed all the oil, fire it up for a little while and check the crank for new oil before it has a chance to spread and cover your entire motor again. SW Quote Link to comment Share on other sites More sharing options...
ptwizz Posted June 19, 2014 Share Posted June 19, 2014 If anything black were coming from the crankcase gasket of a 2 stroke, something would be very wrong. A leak in the crankcase (gasket or crankshaft seals) will lead to poor running at idle as it sucks in air. The spatter marks indicate a leak at the exhaust flange. Have you checked that the exhaust is not clogged with carbon deposits? This would cause poor running at high rpm and leakage due to excess back pressure. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 19, 2014 Share Posted June 19, 2014 Ahhhhhh, thats a very very good point! I remember having to de-coke an exhaust on a little 125 2 storke many many moons ago but the end result was AMAZING ! Not sure you would want to do it in quite the same way as I did though lol (fill it with petrol and let it burn, tap it all out as it cools) but as I say, I would expect this is not the way it's actually done. LOL SW Quote Link to comment Share on other sites More sharing options...
jock Posted June 19, 2014 Share Posted June 19, 2014 Took silencer of left expansion pipe on still the same,going to try another carb.and check spark, on tick over it runs fine just bogs down when you gave it throttle,all the crap around exhaust but plug is very clean,ive put my 37 walbro of my f200 engine which runs perfect on mine still the same on the simonini no go after tick over. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 19, 2014 Share Posted June 19, 2014 It will be the expansion chamber that is coked mate (If at all of course) You would see signs by popping it off the barrel and looking. Well worth the effort I would say SW Quote Link to comment Share on other sites More sharing options...
spigot Posted June 19, 2014 Share Posted June 19, 2014 Have you checked the reed valves are in good condition and sealing properly? Sent from my iPhone using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
jock Posted June 19, 2014 Share Posted June 19, 2014 Exhaust ok clean it your way simon.not checked reeds yet,piston/rings look ok.well the bit we can see, Quote Link to comment Share on other sites More sharing options...
ptwizz Posted June 23, 2014 Share Posted June 23, 2014 Not sure you would want to do it in quite the same way as I did though lol (fill it with petrol and let it burn, tap it all out as it cools) but as I say, I would expect this is not the way it's actually done. LOL SW That is exactly the way it's actually done in my workshop, but to some extent this may be a reflection of my contempt for 2 strokes Quote Link to comment Share on other sites More sharing options...
wallboy Posted June 30, 2014 Author Share Posted June 30, 2014 It turns out it was the carb which was f***ed so all it running ok now Quote Link to comment Share on other sites More sharing options...
Guest Posted July 1, 2014 Share Posted July 1, 2014 Happy days SW Quote Link to comment Share on other sites More sharing options...
ptwizz Posted July 1, 2014 Share Posted July 1, 2014 Could you elaborate upon the technical term "f***ed", so that others may benefit from your experience? Quote Link to comment Share on other sites More sharing options...
wallboy Posted July 1, 2014 Author Share Posted July 1, 2014 Could you elaborate upon the technical term "f***ed", so that others may benefit from your experience? Unfortunately not as I just fitted a brand new Walbro carb and I am back to the same problem I had to start with so not a bloody clue what's going on. Quote Link to comment Share on other sites More sharing options...
wallboy Posted July 1, 2014 Author Share Posted July 1, 2014 OK update: New Walbro carb, wound out the Low setting 1/4 and its running perfect. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.