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PostPosted: Tue Sep 28, 2010 7:15 pm
by Wayne
I sawpped the tachs over and they are fine, then back again and the same numbers run upto 9990. So looks like the motors will come off and new spark leads. then a re-run, I will do the carb kit as well can't hurt after 25 years ? I did manage 5600 on the left and 5400 on the right. they are cracking little motors that wanted to hop over the stops.


PostPosted: Wed Sep 29, 2010 1:01 pm
by Shannon
Historically speaking failure to completely understand and master the 185 engine has ruined many-a Lazair flying endeavour.

Not a bad idea to completely rebuild the carbs or just simply install diaphragm kits if nothing else. Re-adjustment of the carbs (I do it engine running on the stand) as advised is advised. As it states below the engines were only test run... not fine tuned. Probably just as well to pull the engine down to apply grease and maybe check the timing while in there. My experience says Tiny Tachs either work right or erratic. Probably not a problem with the engine itself. OEM sparkplug caps have been well known for popping off in flight. I utilize NGK LB05EZ's. Heads should be torqued every 5hrs or so up to 25. Manual states check every 100. Torque in small increments up to 210-220 in/lbs. Check carbs nuts often if not wired. Lastly it's entirely normal for the engines to weep and seep oil from the Head, Base, and Case-Half gaskets as well as the compression releases. The crankshaft seals however should not leak or weep much if at all.

Think the engines pull hard now. Pop on some better props !