My yamaha 85 2 stroke is not firing on the #3 cylinder until the rpm gets above 3000. Makes the hole shot very sluggish. Here are some things I have done to diagnose the problem:
Compression check: #1 and #2 at 100psi, #3 at 95psi
Cleaned carbs
switched carbs between #1 and #3 - drop cylinder test still shows #3 to be the problem
Switched coils - drop cylinder test still shows #3 to be the problem
Any help or ideas would be appreciated.
This is not a fuel problem. Pull and clean/replace the plugs. Check the plug wires. If those are fine and the coils have been eliminated, this would leave the power pack or timer base. I would suggest checking all connections pertaining to both. If a problem is not located and you have a meter with a peak voltage adapter or one with that capability (most meters are RMS voltage), you can find the instructions to troubleshoot further in the motor’s shop manual or on CDI’s website. If you get the instructions from CDI and the parts on the motor are factory, the numbers may vary a little but the theory is the same.
2013 Ranger Z21 Intracoastal 250 hp Yamaha VMAX SHO
an issue with the reeds on that cylinder would also cause that symptom
Thanks for the ■■■■■■■■. How do I check the reeds?
pull the carbs and turn over the motor and watch the “flaps” move
a bad spark plug will also cause that issue, had that happen earlier this week
Just wanted to provide an update in case anyone else has this problem. The problem turned out to be a bad fuel pump. On these motors the vacuum port for the pump is in line with the #3 cylinder. If pump is bad it floods the bottom cylinder. Easy fix, running like new
yes sir
the symptom to look for is a wet spark plug on the #3 cylinder
you can tell alot about a motor by “reading” the spark plugs