175 hp evinrude backfiring

[payatz]

Hi all.... I changed the voltage regulator on my 1991 175 hp crossflow and now the engine backfires severely and wont start.... i had to pull the flywheel off to do this and changed one of the flywheel magnets as one had moved and was touching one of the other magnets. Does anyone know if the flywheel has to be put back in a certain spot as my manual says the shaft should be keyed but mine isnt.... and if it does,does this change the timing or is there anything else that would change the timing so dramatically.....any help would be much appreiated....thanks

[FNQCairns]

You sure it's not keyed? The nut toque needed to stop a flywheel spinning without a key is extremely large.

Does the book tell you how to do a FULL static time? This is what you need to do now, you sure there is no keyway?

cheers fnq

[payatz]

Thanks for the reply...Yes its not keyed..its a tapered shaft with no key.. the flywheel itself has a spot for a key but thats it? weird eh?

[FNQCairns]

I simply cannot remember, I have seen those engines stripped down and even had my hands dirty but I cannot remember no crank keyway.

Try here: http://forums.iboats.com/forumdisplay.php?f=24

Join and copy your post over, the search function is good also, there are some good engine model Gurus on this site and they should sort you out.

If not try here:http://forums.screamandfly.com/forums/forumdisplay.php?f=20

These blokes know almost all.


cheers fnq

[captain rednut]

hi payatz it should have a key for sure, have you checked the old key hasent sheared off flush on the crank making it look like its flush? thanks jim

[station-rat]

I think Captain Rednut is right on the money.
It must have a keyway

[Spaniard_King]

Definately has a key. I wouldn't try anything untill you have the flywheel keyed correctly.

[payatz]

Thanks all..... yep idiot here cleaned shaft properly and found sheared key.... a woodruff key at that..... just like in the manual funnily enough! Now i know why the stupid flywheel was so hard to remove....sheared key wasnt helping! As for the timing and backfiring i'll have to find or make a new key and see what happens after that...i still dont understand about the whoe backfiring bit though?

[FNQCairns]

Yes good it was a highly suspected outcome and it all ends up good.

Whatever you do don't make a new key, buy the correct genuine article and make sure you take absolute and full notice of the torque specified.

If you are rough here you may chip the crank keyway which will make the engine a junker.

You timing was out (backfiring) due to the flywheel being out of alignment keyway to keyway.

Still I dunno the history of the engine but if any fiddling has been done best to do static time first - at least you will know if it is in the ball park for the first start.

cheers fnq

[payatz]

Thanks fnq will do..............