1990 yamaha dropping spark sometimes

stanley1356

Recruit
Joined
Sep 8, 2012
Messages
3
Hello all,

I have a 1990 yamaha that was rebuilt this summer as the piston skirt was cracked. Now that she has been rebuilt it only runs well 'sometimes'. The number two cylinder loses spark for no reason. ALL electrical has been replaced......CDI coils everything. Boat runs really well for 30 40 minutes then starts dropping spark in the number two. Mecahnics are stumped, never seen anything like this. Anyone have any ideas?

Thank you
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: 1990 yamaha dropping spark sometimes

it might help if you posted what motor you are dealing with
 

phockeye

Cadet
Joined
Jul 21, 2012
Messages
13
Re: 1990 yamaha dropping spark sometimes

if mechanics are stumped you have a problem, I would try a high speed shut down (as soon as failure occurs) and check spark plugs for signs of water could be a leaking gasket or cracked head
Hello all,

I have a 1990 yamaha that was rebuilt this summer as the piston skirt was cracked. Now that she has been rebuilt it only runs well 'sometimes'. The number two cylinder loses spark for no reason. ALL electrical has been replaced......CDI coils everything. Boat runs really well for 30 40 minutes then starts dropping spark in the number two. Mecahnics are stumped, never seen anything like this. Anyone have any ideas?

Thank you
 

stanley1356

Recruit
Joined
Sep 8, 2012
Messages
3
Re: 1990 yamaha dropping spark sometimes

if mechanics are stumped you have a problem, I would try a high speed shut down (as soon as failure occurs) and check spark plugs for signs of water could be a leaking gasket or cracked head

Thanks for your replies guys. The engine is an outboard ELTD. The gasket was replaced and the head is not cracked. I have been in the boat when it runs, runs like a top, then just loses spark in the number two. Problem comes and goes, more often than not though.
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: 1990 yamaha dropping spark sometimes

We figured it was an outboard and ELTD tells us nothing about size just that it's mid 80's, long shaft and electric start
 
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