I guess the post title is a misnomer. It’s more like spring projects. I haven’t done too much this winter, although I have poked around the engine compartment a good bit, and I determined a couple things related to the cooling pumps on my 2gm20f.
First, my neighbor, who is a certified boat tech, had led me to believe that both pumps were on the way out. My inspection seems to indicate otherwise. His opinion is based on the presence of weeping evidence from the weep hole on the bottom side of each pulley assembly. I, on the other hand, have done a more thorough inspection. Having removed the raw water pump, I determined that there is no problem with the pump. I can see very little evidence of leaking, and the bearing has absolutely no play in it. I carefully inspected the coolant circulation pump as well. Again, I seen no evidence of leakage, and the bearing is in great shape. So I’m not replacing these pumps. Never had a cooling problem, never lost any appreciable amount of coolant.
Sometimes the “experts” are wrong. To be fair, he works on boats that cost deep into six figures, owned by people who never blink about the cost of maintenance or repairs. If there is a hint of trouble, just replace it. I don’t have the financial luxury of replacing stuff just because there might be evidence of a problem discovered by a 90 second inspection. I’m not replacing those pumps.
Second, I haven’t found my oil leak yet. There has been no dripping oil since I’ve hauled the boat, but of course, the engine hasn’t run during that time either. If it’s a main seal, it likely won’t drip without having the engine running. I’ll have to wait and see on that one. If I need to, I can pull the engine out off the beds while it’s in the water and change the seal then. Only takes about a day or so to do that.
Third, I’ve decided to reuse my old prop shaft that I replaced in 2016 (linked here ). I read up about the reason prop shafts are replaced (should have done this 3 years ago instead of just assuming). Doesn’t seem to be much risk of shearing the shaft at a place where there is pitting. The main problem with the corrosion is that the un-smooth finish can disturb seals and shorten the life of cutlass bearings. I definitely haven’t had that problem. So back in it goes. Yesterday I cleaned up the shaft, inspected the coupling and packing nut, and got it all ready to install. I’ll probably do that tomorrow, as we’ve got a stretch of nice weather ahead of us.
Reassembled shaft and coupling. I was concerned that the coupling would need to be replaced because the key had been sheared. It was fine after a little dressing with a file.
The high-quality Buck Algonquin shaft log hose is still in perfect condition.
Cleaned up stuffing box and hose reassembled.
And here’s the assembly ready to go into the boat. Of course, the coupling has to come off the shaft and be slotted through the shaft log, then coupling reattached to the end of the shaft. Not sure where those black bands came from. A glitch in the photo upload, I guess.
The prop – I still have the old prop from before I repowered 12 years ago. If I recall correctly, it allowed the engine to rev 400-600 rpm too high. I got another prop second-hand, that was amazingly close to the right dimensions, and brought the rpms into an acceptable range. Of course, that prop is now somewhere on the bottom of the bay. So I’ve been researching props a good bit. I’ve used the prop calculator on boatdiesel.com a number of times, sometimes with differing results (I could have sworn I entered in all the correct information each time. . .). I visited with a prop expert near me, and learned some interesting things. First, it is impossible to cover all the variables for calculating a prop simply by using an online tool like that. You can get near the ball park. Notice I didn’t say in the ball park, I said near. Second, having a base line from which to calculate a prop size is pretty important, and I have that with the old prop. Seems like I can get pretty close to the right size and pitch by knowing the error margin of the old prop. Fortunately, this shop (digitalpropshop.com) has prop on consignment for a very good price. This is a three-blade wheel, vs the two-blade wheel I had before. Definitely not going to do any racing now, but I’m eager to see how the new prop performs compared to the old. He said it would be better balanced (less vibration) just by virtue of being a three-blade wheel.
And that’s it for now. I’ll keep you posted.