Miss-Firering Yamaha F-225 TXRA 4-stroke

[Arty]

I have a 9/2001 Yamaha f-225 TXRA 4-Stroke which has a slight miss. I think that the problem is on the right cyl.. I pulled the plugs and they have flat black on the threads and the left side was clean. Last year the boats lower unit skimmed over a sand bar. Is it possable that the cam could have jumped a tooth. Would anybody know how to line up the cams so it can be seen from the belt, if there out of line.
Or does any body have any other thoughs.
Thanks

 

[rodbolt]

Re: Miss-Firering Yamaha F-225 TXRA 4-stroke

unless a drive belt or chain breaks it wont jump time.
to check it you can remove the flywheel cover, rotate the flywheel to TDC,look at the alignment marks on the cam sprockets. they will either line up or be 180 apart. if apart totate the flywheel again one revolution to line up tdc again.
then go clean the fuel system and injectors.
that engine uses a 12V TCI waste spark ign system. 2 cylinders on opposite banks will fire at the same time just on cylinder will be on the exhaust stroke and the other on a compression stroke, hence the term waste spark.