johnsw
Well-known member
Looking to find out what prop folks might be using with similar hull / engine. Curious what WOT RPM you may be reaching.
For a while now (years), my WOT max RPM has been running a pretty consistent 4800 rpm. The last inch or so of throttle produce no increase in RPM. Adjusting trim angle doesn't help much. No issues at idle and engine seems to be running fine at full throttle, but not really sure I'd hear or feel an engine miss or anything at that point. Acceleration is good. Ignition system was gone though last season to diagnose and correct failing stator problem. Carbs were also overhauled in the process. I've checked WOT static timing and adjustments and they look correct. Compression check is one of the few remaining things I can think of to check.
Have always had the same spec 3 blade SS 14.25 x 16 prop that came with the boat when new back in '04. Wondering if it may be time to try tweaking the prop to see if I can get some rpms back if everything else mechanically checks out.
The yam manual has WOT spec as 4500 - 5500 rpm, so technically I'm in spec. But I'd like to be closer to the higher number rather than being on the low side.
Any thoughts?
Thanks
Followup question to anyone who has done prop testing? Reading that too much pitch loads the engine and lowers WOT rpm, does that give the symptom of having a dead spot on the throttle where the rpm goes no higher? Visual check looks like the throttle plates are operating full range of the throttle control.
For a while now (years), my WOT max RPM has been running a pretty consistent 4800 rpm. The last inch or so of throttle produce no increase in RPM. Adjusting trim angle doesn't help much. No issues at idle and engine seems to be running fine at full throttle, but not really sure I'd hear or feel an engine miss or anything at that point. Acceleration is good. Ignition system was gone though last season to diagnose and correct failing stator problem. Carbs were also overhauled in the process. I've checked WOT static timing and adjustments and they look correct. Compression check is one of the few remaining things I can think of to check.
Have always had the same spec 3 blade SS 14.25 x 16 prop that came with the boat when new back in '04. Wondering if it may be time to try tweaking the prop to see if I can get some rpms back if everything else mechanically checks out.
The yam manual has WOT spec as 4500 - 5500 rpm, so technically I'm in spec. But I'd like to be closer to the higher number rather than being on the low side.
Any thoughts?
Thanks
Followup question to anyone who has done prop testing? Reading that too much pitch loads the engine and lowers WOT rpm, does that give the symptom of having a dead spot on the throttle where the rpm goes no higher? Visual check looks like the throttle plates are operating full range of the throttle control.