I am repairing a 1990 Yamaha V4 115 2 stroke (115 ETLD) for my parents and need to confirm I am on the right track or if I need to look into something else.
Original issue, out on the water and the engine would not stay running unless at high RPM's, just did not want to idle after initial startup. Ran fine for about a minute in the water then struggled to stay running at idle and was hard to start. Boat was just purchased so they have no history of the engine other then the guy supposedly used it yearly and even took it out of state for fishing tournaments.
Seemed like a fuel issue aka carb problem. Took the carbs off and cleaned them up, new kits in them and reinstalled them. Started it on the muffs and after about 30-45 seconds of running good it started to have a pretty hard cough that seems like it could be from one cylinder misfiring maybe and it would cause the engine to either stall or come pretty close. I tried elevating the RPM's at in the 2,000-2,500 rpms it still seems to have a miss to it.
After some searching it points to being a lean idle sneeze/cough. I drained the old gas and put fresh in in case that was an issue. New fuel filters as well. Plugs are new. Have the trip on the water and my run time on them. Compression is good, 120 PSI in all cylinders. I also installed a new fuel pump.
Since I can get the engine to run fine for approx. 30-45 seconds then it has the cough that can stall the engine or come very close. When it stalls the engine I have a really hard time getting it to restart. To get the engine to run fine again I need to let it sit for approx. 30 minutes then I can get another good 30-45 seconds out of it.
Is this still a lean sneeze issue and I should tear apart the carbs again in case the old fuel plugged something again? Is it possible I have a bigger issue? Should I look into a timing issue? Ignition issue?
I'm pretty fluent in automotive engine repair but have limited experience in outboards but I do have the manual for this engine if timing needs to be checked as hopefully it explains the process.
Original issue, out on the water and the engine would not stay running unless at high RPM's, just did not want to idle after initial startup. Ran fine for about a minute in the water then struggled to stay running at idle and was hard to start. Boat was just purchased so they have no history of the engine other then the guy supposedly used it yearly and even took it out of state for fishing tournaments.
Seemed like a fuel issue aka carb problem. Took the carbs off and cleaned them up, new kits in them and reinstalled them. Started it on the muffs and after about 30-45 seconds of running good it started to have a pretty hard cough that seems like it could be from one cylinder misfiring maybe and it would cause the engine to either stall or come pretty close. I tried elevating the RPM's at in the 2,000-2,500 rpms it still seems to have a miss to it.
After some searching it points to being a lean idle sneeze/cough. I drained the old gas and put fresh in in case that was an issue. New fuel filters as well. Plugs are new. Have the trip on the water and my run time on them. Compression is good, 120 PSI in all cylinders. I also installed a new fuel pump.
Since I can get the engine to run fine for approx. 30-45 seconds then it has the cough that can stall the engine or come very close. When it stalls the engine I have a really hard time getting it to restart. To get the engine to run fine again I need to let it sit for approx. 30 minutes then I can get another good 30-45 seconds out of it.
Is this still a lean sneeze issue and I should tear apart the carbs again in case the old fuel plugged something again? Is it possible I have a bigger issue? Should I look into a timing issue? Ignition issue?
I'm pretty fluent in automotive engine repair but have limited experience in outboards but I do have the manual for this engine if timing needs to be checked as hopefully it explains the process.
