89 Evinrude 20hp on a 1436 Weldbilt (used for duck hunting). Motor starts great, idles, and runs well. After a little use after purchase, it felt like the boat was losing power while accelerating (like a gear slipping) even though the RPMs stayed the same... it was a jerking motion. I replaced the prop with a Solas. It ran great on 4 more outings through flooded timber, then started slipping again. I took the boat out again the next day, same prop, no slippage.
Boat goes out 2 days later and we can't get above a fast idle before the slipping starts. We moved weight forward and aft. The motor is low in the water (probably 3" lower than it should be). I marked the prop and hub before last outing, and the marks still line up, even with it feeling like it's spun.
I'm really at a loss here. All my symptoms say it's a spun prop, but the marks aren't moving on the prop/hub. I don't think it could be a ventilation issue, as it doesn't ever "grab" the water... it just keeps lurching, but the rpms never change and the motor sounds great.
What am I missing?
Boat goes out 2 days later and we can't get above a fast idle before the slipping starts. We moved weight forward and aft. The motor is low in the water (probably 3" lower than it should be). I marked the prop and hub before last outing, and the marks still line up, even with it feeling like it's spun.
I'm really at a loss here. All my symptoms say it's a spun prop, but the marks aren't moving on the prop/hub. I don't think it could be a ventilation issue, as it doesn't ever "grab" the water... it just keeps lurching, but the rpms never change and the motor sounds great.
What am I missing?
