I have a 4HP Merc 1cyl outboard on my dinghy. After a batch of bad gas it was running poorly so I removed, cleaned and re-installed the carb. On a quick test ride, I brought it up to full speed. It ran great!
Until I hit the log. The engine kicked up and there was no visible damage to the prop, but I apparently spun out the hub of the prop. The engine still ran great, but at high speed the prop would start to slip.
It's clearly marked as 7 pitch, and the manual provided the diameter, 7.8". Amazon to the rescue, ordered my Merc 7 pitch 7.8" diameter and popped it on.
Now it seems to cavitate a lot at any speed and can go maybe half the speed as before the log incident. By sound (no tach) it only revs up to maybe half the prior RPMs.
Careful comparison shows both props are indeed the same diameter, both are marked as 7 pitch, but the blade shapes are different. The old one seems to have longer, thinner blades.
Any ideas what's going on here?
Until I hit the log. The engine kicked up and there was no visible damage to the prop, but I apparently spun out the hub of the prop. The engine still ran great, but at high speed the prop would start to slip.
It's clearly marked as 7 pitch, and the manual provided the diameter, 7.8". Amazon to the rescue, ordered my Merc 7 pitch 7.8" diameter and popped it on.
Now it seems to cavitate a lot at any speed and can go maybe half the speed as before the log incident. By sound (no tach) it only revs up to maybe half the prior RPMs.
Careful comparison shows both props are indeed the same diameter, both are marked as 7 pitch, but the blade shapes are different. The old one seems to have longer, thinner blades.
Any ideas what's going on here?