Boat is a 1990 Mako 23 Cuddy, motor is a 1999 Mercury EFI 225
Symptoms:
Ran out this morning and when throttled up to ~3K, motor surged and raced to 4k+.
Figured it to be a spun hub, so went over to a sandbar, set anchor, hopped out and swapped prob with a spare. Problem continued, motor would run normally up to about 2k, but over 2k there was a lot of surging and racing. Engine would jump up in RPM's with no sign of corresponding increase of speed.
Also noticed a high pitched whine as the RPMS went over 2k.
The prop I started with today is 19" pitch and the hub was new in June after a similar surging incident - changing hubs alleviated the issue. Quicksilver prop and Flo Thru Hub.
The prop I replaced it today with was purchased new in June and also had a new hub but is a 17" pitch. Running it, the boat felt really slow, and was not performing to what is normal. Never got up past 4k RPMs, as there was a lot of surging and racing so it did not seem prudent. It did seem like the motor was easily going to hit the red line with the 17, which it did not do back in June the last time I had that prop on the boat.
I had not run the boat in 2 weeks, but it ran normally the last time out. Boat has been in the water this summer. There is some additional growth on the hull and it felt very sluggish. The noise from the motor seemed consistent with a spun hub or ventilation, though the water ahead of the motor seemed clear.
Where should I be looking for the issue? Another hub/prop? Lower Unit? Fuel delivery?
Also noticed that the prop shaft has about 1/16" to 1/8" of play with the prop installed, which I don't recall occurring previously.
Symptoms:
Ran out this morning and when throttled up to ~3K, motor surged and raced to 4k+.
Figured it to be a spun hub, so went over to a sandbar, set anchor, hopped out and swapped prob with a spare. Problem continued, motor would run normally up to about 2k, but over 2k there was a lot of surging and racing. Engine would jump up in RPM's with no sign of corresponding increase of speed.
Also noticed a high pitched whine as the RPMS went over 2k.
The prop I started with today is 19" pitch and the hub was new in June after a similar surging incident - changing hubs alleviated the issue. Quicksilver prop and Flo Thru Hub.
The prop I replaced it today with was purchased new in June and also had a new hub but is a 17" pitch. Running it, the boat felt really slow, and was not performing to what is normal. Never got up past 4k RPMs, as there was a lot of surging and racing so it did not seem prudent. It did seem like the motor was easily going to hit the red line with the 17, which it did not do back in June the last time I had that prop on the boat.
I had not run the boat in 2 weeks, but it ran normally the last time out. Boat has been in the water this summer. There is some additional growth on the hull and it felt very sluggish. The noise from the motor seemed consistent with a spun hub or ventilation, though the water ahead of the motor seemed clear.
Where should I be looking for the issue? Another hub/prop? Lower Unit? Fuel delivery?
Also noticed that the prop shaft has about 1/16" to 1/8" of play with the prop installed, which I don't recall occurring previously.