Sick Zen engine

Have a stock zen other day it acted like it was out of gas went out to get it still had half tank but acted like it ran out got spark and fuel but she wont starthave comp too someone said timing key maybe but where is this lookin in manual but dont se it just wont fire

Look at this article: www.modelgasboats.com/Magazine...h_Teardown.html You will see how to get to the timing key. It is the key holding the flywheel on the crank. See if it's not sheared. If you have spark, compression and fuel it should pop unless as mentioned, the timing is way off.

----and after you get it back together make a mark on the flywheel that corresponds with the piston position in the cylinder then you can easily tell when a key is stripped. I use the top of the ring at the top of the exhaust port and a metal marker paint mark on the flywheel next to the red coil pole piece as reference points. REMEMBER to rotate the engine in the proper direction when doing this !!! Then it is easy to check if there is any question about the flywheel being out of position. Ed

Good tip!

thanks to all i think i found it pulled jug this morn an ring was stuck on arrow side of piston got smalll scar on pis an jug didnt break ring tho havent check timin key yet tho but all ur help was deff. app. ty RJ

Ron,

Clean out the ring groove on the piston and clean the ring. Make sure it moves freely in the ring gap when you reinstall it. I have not seen the physical damage to your engine, but I can tell you that they usually will run just fine even after some overheating...they are tough little engines! Assuming the scoring is minimal, I would give it a try. Don't bother going to the flywheel just yet. The problem is most likely the ring sticking.

Some things to make sure:

- 1 USG of gas with 8 oz of good synthetic oil...make sure of this! (1 USG= 3.8 liters).
- Carb setting on 813 should be somewhat like the stock carb. Try 1 1/4 on LOW and 1 5/8 on HIGH. This will be rich for the 813 and the low might have to be closed in later, but it should run.

Keep us posted

The two things I replace fairly often are the carb pressure regulator diaphragm and the piston ring. Neither cost much and both have a big effect on performance.

Lohring Miller

Addendum to earlier post

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Reference point on piston should be taken with the piston on the UP stroke with proper rotation. Ed