Larrygrandmarquis 0 #1 Posted July 21, 2021 pro gravley model 987071 serial 000126 robin engine eh410ys73104350 it stalled with the engine cold after les than a minute with the choke pushed in so I restarted it an ran it 1/4 choke in the vid I replaced the gas filter ran it with no air filter and one on checked the gas pump put a new plug in adjusted the valve top dead center with my finger in the plug hole so I knew I was on the compression stroke it has 91 hours on it and my zip is 21209 and I am on food stamps so I have to do this my self. I am including the you tube vid I took also I replaced the needle valve and cleaned the carb I do not have a compression checker I noticed when I looked at the valve gap the intake was so tight I could not fit that smallest feeler gauge but the exhaust was sloppy not sure the gap but a lot bigger. What do you think is the problem? tractor vid shaky hands 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,481 #2 Posted July 21, 2021 Page 38 of the service manual Share this post Link to post Share on other sites
Jeff-C175 7,195 #3 Posted July 21, 2021 (edited) Hi Larry, keep in mind that you shouldn't run the engine for very long with the tins removed as the cooling air across the engine will be greatly diminished. @Larrygrandmarquis Edited July 21, 2021 by Jeff-C175 1 Share this post Link to post Share on other sites
Larrygrandmarquis 0 #4 Posted July 22, 2021 ok but I could not find fellers that went as low as 0.085mm just what I said in the vid. and it still backfired threw the muffler not carb so what is the problem? Share this post Link to post Share on other sites
Jeff-C175 7,195 #5 Posted July 22, 2021 51 minutes ago, Larrygrandmarquis said: backfired threw the muffler Just a wild guess Larry, maybe it threw the exhaust valve seat? you said exhaust was real loose. maybe seat came loose and hanging the exhaust valve open. Share this post Link to post Share on other sites
Achto 26,504 #6 Posted July 22, 2021 @Larrygrandmarquis Commonly if the engine is mechanically sound, a back fire through the exhaust is a symptom of the engine running too rich. A back fire through the carb is a symptom of the engine running too lean. You mentioned that you are running at 1/4 choke in the video. Does turning the choke off make it run better or worse? Share this post Link to post Share on other sites
953 nut 51,520 #7 Posted July 22, 2021 Aslight bit of fuel starvation could be an indication the fuel system needs a bit of attention. If you have been running fuel with ethanol please STOP! Ethanol will cause problems i the fuel system. You can find a statio that sells real gas here, https://www.pure-gas.org/. Share this post Link to post Share on other sites
Larrygrandmarquis 0 #8 Posted July 22, 2021 7 hours ago, Achto said: @Larrygrandmarquis Commonly if the engine is mechanically sound, a back fire through the exhaust is a symptom of the engine running too rich. A back fire through the carb is a symptom of the engine running too lean. You mentioned that you are running at 1/4 choke in the video. Does turning the choke off make it run better or worse? choke off it is worse. Share this post Link to post Share on other sites
Larrygrandmarquis 0 #9 Posted July 22, 2021 16 hours ago, Jeff-C175 said: Just a wild guess Larry, maybe it threw the exhaust valve seat? you said exhaust was real loose. maybe seat came loose and hanging the exhaust valve open. How do I find out with out taking all of the top of the engine apart? Share this post Link to post Share on other sites
Larrygrandmarquis 0 #10 Posted July 22, 2021 7 hours ago, 953 nut said: Aslight bit of fuel starvation could be an indication the fuel system needs a bit of attention. If you have been running fuel with ethanol please STOP! Ethanol will cause problems i the fuel system. You can find a statio that sells real gas here, https://www.pure-gas.org/. their not near me sorry to say. Share this post Link to post Share on other sites
Jeff-C175 7,195 #11 Posted July 22, 2021 1 hour ago, Larrygrandmarquis said: How do I find out with out taking all of the top of the engine apart? If you have an air compressor and are able to fashion a fitting to put air from the compressor into the spark plug hole, you can perform a rudimentary 'leak down' test. You feed a little air into the spark plug hole with the cylinder at top dead center and then listen at the exhaust and at the carb for sounds of air exiting. It won't necessarily tell you if it's the valve seat popped out, but it WILL tell you if the valves are leaking. Share this post Link to post Share on other sites