daraghcummins
Cadet
- Joined
- Mar 17, 2010
- Messages
- 17
Hi all,
I'm new and I need help; I have a 1986/7 vintage Yamaha 115 V4 2 stroke engine giving me trouble.
To start at the beginning the engine overheated and as a result I had to be rebuild in one cylinder. At the time I discovered this one cylinder had no compression and when I dug deeper I discovered the cylinder was scored and the rings has become one with the piston.
When rebuilding I honed the cylinder as a re-bore was not necessarily essential. Acting on advice I decided to go with the hone option and fitted a standard piston. Now rebuilt the 3 cylinders that where not rebuilt have a reading of 105 PSI and the cylinder I rebuilt has a reading of 100 PSI which according to my Yamaha manual is ok????
When the boat reaches operational temperature the engine acts as if it is starved of fuel/air and chucks. Once it cools it is fine again so the issue is clearly temperature related. The boat starts on the button every time.
I have replaced:
Big Ends / Small Ends,
All engine seals and gaskets,
Plugs,
Thermostats,
Coils (used),
Fuel Pump,
Heat sensors on block,
All pink wires,
All intake gaskets,
Balanced the carbs,
Replaced the fuel tank and lines,
Fuel Pump,
Power pack box (ECU Box),
Replaced the male/female fuel connection &
other adjustments.
Any suggestions as to what my issue might be are welcome, I am running out of ideas. From what I can gather it is either an intake airflow issue or electrical issue due to heat/pressure.
Hope someone has an idea or two.
Thanks,
Daragh.
I'm new and I need help; I have a 1986/7 vintage Yamaha 115 V4 2 stroke engine giving me trouble.
To start at the beginning the engine overheated and as a result I had to be rebuild in one cylinder. At the time I discovered this one cylinder had no compression and when I dug deeper I discovered the cylinder was scored and the rings has become one with the piston.
When rebuilding I honed the cylinder as a re-bore was not necessarily essential. Acting on advice I decided to go with the hone option and fitted a standard piston. Now rebuilt the 3 cylinders that where not rebuilt have a reading of 105 PSI and the cylinder I rebuilt has a reading of 100 PSI which according to my Yamaha manual is ok????
When the boat reaches operational temperature the engine acts as if it is starved of fuel/air and chucks. Once it cools it is fine again so the issue is clearly temperature related. The boat starts on the button every time.
I have replaced:
Big Ends / Small Ends,
All engine seals and gaskets,
Plugs,
Thermostats,
Coils (used),
Fuel Pump,
Heat sensors on block,
All pink wires,
All intake gaskets,
Balanced the carbs,
Replaced the fuel tank and lines,
Fuel Pump,
Power pack box (ECU Box),
Replaced the male/female fuel connection &
other adjustments.
Any suggestions as to what my issue might be are welcome, I am running out of ideas. From what I can gather it is either an intake airflow issue or electrical issue due to heat/pressure.
Hope someone has an idea or two.
Thanks,
Daragh.