Friday, September 10, 2004


I'm grounded for the moment until the replacement engine comes. The engine is coming from Michigan. I live in Alabama. UPS takes about 4 days to ship a package between these points. The guy said he would send the replacement out on Monday. Thursday comes, no engine. Friday comes, no engine. I called the guy back asking why my engine hadn't arrived. He said he hadn't had a chance to send it out. I tell the guy that I'm really disappointed and now I'm going to miss another weekend of flying because he didn't do what he said he would do. He tells me he will make sure it gets out the following Monday.

The engine arrives on Thursday, as expected, only there's a problem. The fan shroud was damaged in shipping and I can't turn the engine over because of interference with the fan. The piece of plywood that the engine was secured to was too thin and it broke, allowing the engine to move around, thus causing the damage. I call the guy and tell him the story. He says he's going to call UPS and request an insurance claim. In the meantime he tells me to put the damaged shroud on the 377 and repackage it in the original box and UPS will pick it up. At this point I'm wondering about the integrity of this individual, because I'm pretty sure what he told me to do wasn't Kosher. I did it anyway because I didn't want any more delays in my flying season. The guy said he would send me another fan shroud for the 503.

Well, I couldn't re-use the plywood from the original package because it was broken in two pieces. I had some three-quarter inch exterior plywood laying around and I cut a piece to match the original box, and after stripping the 377 of all the parts I needed to switch, boxed it up. UPS picked it up the next day.

It just so happened that about a month earlier, I had purchased a Rotax 503 on eBay for a good price, hoping to rebuild it and put it on my MX. I took advantage of the extra parts and put the fan shroud from my junk engine on the 503 that I just received. The only problem with this is that I had a CDI (electronic) ignition that I wanted to use on this 503, but the fan shroud from my old engine was for points. I decided to use the older points ignition on this engine because this engine was originally a points engine anyway and had the cam machined on the crankshaft to actuate the points. I had never setup a points engine before and it took me about 4 hours to get it right. I had to use a dial indicator and a multimeter and I was following a technical manual step-by-step. Now that I know how to do it, I could do it in less than an hour. I did this all on Saturday, and Sunday I took it to the hangar to at least attach the engine to the airframe of my MX. It took me longer than expected because the mounting bolts for the 503 are different than the 377 and I had to modify some mounting brackets. I got the engine attached and it was getting dark, so I let the job uncompleted.

One day during the following week, I left work early and went to the hangar and finished the engine installation. I started the engine with the fuel that was from the second container that I mixed a few weeks ago. It started fine, but smoked and sputtered and quit, just like the symptoms with the 377. I drained the fuel and went to the gas station an bought some fresh fuel and mixed it properly with fresh oil. I poured a bit of this fresh fuel into the tank and after a bit of rough running to burn out what was left of the old fuel, the engine ran fine. I don't know how I did it, but apparently I had succeeded in mixing two separate five gallon containers of fuel with too much oil! This was the reason that the first engine quit and wouldn't start. Lucky for me, I found a flaw with the old engine during this process, one that would have caused a failure sooner or later, and probably while in flight. I counted my blessings and was happy that God was looking out for my well being, and thanked Him accordingly!

One small problem remained. Going from the 35 horsepower engine to the 46 horsepower engine meant that I needed to increase the pitch of my propeller to keep from over-revving the engine and to get the Cylinder Head and Exhaust Gas Temperatures correct (CHT/EGT). I had to order some more blocks to give the prop more pitch, which would delay me another week.

The new pitch blocks came and were installed on the following weekend. I tied the plane down and tested the engine with the new prop pitch. Bummer, still not enough pitch. I was done for that week and still wasn't flying.

The newest set of pitch blocks arrived the following Friday and were installed on Saturday. The engine was tested and this time, the pitch blocks were correct. The engine would spin at no more than 6250 RPM, which was perfect. I ended up with 16 degree pitch blocks. The 377 was using 12 degree pitch blocks with the same propeller! I was in for a performance upgrade for sure! I completed the rest of the adjustment and re-jetting process to bring my EGT and CHT to the proper levels, and I was ready to fly!


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