Monday, July 25, 2011

Water Pumps

No clever title. This isn't that sort of post. No pictures. They wouldn't be pretty.

Yesterday we were out on the Bay. After some relaxing spinnaker sailing in lights winds, we retired to a beach area, where we could anchor in 5 feet of water over a hard sand bottom and just float. Watching the world drift by from only a few inches above the water is my favorite summertime perspective. The water was a perfect 85 F, the jellyfish are late this year in the Bay, and nothing seemed threatening. Just people laughing and clouds drifting by. In a few days we will be heading out for a 7-day cruise. All was right with the world.

One of the engines over-heated on the way back. I suspected a water pump impeller, which I should have changed when it was hauled last week, but I thought there might be another season in it. My last engines (Johnson and Nissan) would go 10-20 years on an impeller, but not Yamaha; they self destruct every few years. I don't think much of Yamaha 9.9s. I don't think much of the lock down mechanism, the carbs, or the cooling system. Mostly, the cooling system.

I checked all of the usual easy suspects:
  • Intake clear.
  • Outlet hose clear.
  • Thermostat clear... and no water comes out when the engine is started....
... which leaves the impeller, since there are no restrictions between the thermostat and pump. Which is not fun to remove in the water. Water with an oily sheen here and there, a few jellyfish trying to move in, and a mud bottom that would reach my knees if I pushed down. No option, really, with a long-anticipated trip only a few days away: hauling is expensive and would take too long; simply going with one engine is possible, but with little wind predicted that could make for some long days. Going to a nice beach to do the work is always possible--I do that sometimes--but that would hamstring the inevitable trips for parts--and there were several--and there tends to be a bit more wave action. Oil and mud it would be.

I won't give a blow-by-blow--it's in the manual--just a few tips for anyone who must do this in the water. I assure this all took longer to do than to describe (2 hours?).
  • Experience it on dry land first. Water is a less cooperative environment.
  • Don't drop anything. Go slowly, it will be faster in the long run.
  • In the water in the shade is not much worse than in the sun at 100 F; at least you don't sweat. I think that's the only up-side.
  • Get a floating tool boat. I used a plastic concrete mixing pan and found it perfect; it holds plenty of tools and parts, floats high, and would be quite difficult to tip. Drill holes in the flange for 1/4-inch line so you can tie it where you need it. I'm going to remember this trick!
  • Shift the engine into reverse; this way you can reach the nut securing the lower half of the shift linkage.
  • Tie the engine lift line further up the leg.
  • Disconnect the shift linkage. Gently. Soaking with PB Blaster might be wise. If this breaks your going to spend hours pulling the engine and then spend hours pulling the engine from the casing; it connects in a terrible place.
  • Remove the 4 bolts holding the lower unit.
  • Install the lower unit puller. This is a sandwich of two 4x4s carved out to fit the leg just above the cavitation plate; they pinch tightly, secured by through bolts or lag bolts.
  • Beat the lower unit off with a hammer, working your way around. Not easy. Don't bother with prying tools; pounding works better and surprisingly, risks less damage. Don't go too big on the hammer or you risk the motor mount (18-23 ounce, no sledge hammers).
  • Replace the impeller up on deck. Easy. Since engine was in reverse, turn the prop in reverse so that the impeller vanes are bent the correct direction. Change the oil if you feel it is due.
  • Coat the mating surface, bolts, and guide pins with your favorite anti-seize. I like Teflon paste.
  • Install the lower unit. It will slide right on, no matter how miserable removal was. It can take a little fiddling to get the shaft back in the hole. Giggle the prop and it will only take a few seconds. Do not tighten the bolts yet; complete the next step first.
  • Reconnect the shift linkage. Teflon paste on that too; if it seizes and you twist it off you are so screwed. The upper half is very difficult to replace (I broke one on a motor I was stripping for parts).
  • Tighten everything. Put the pull-up rope back where it belongs.
  • Shower off the funk you've been swimming in. Shower the tools too.
Drink a cold one and think about next week, cruising the Bay, and not wondering about engine temperature.

Which is easier: pulling the engine or swimming? For me, swimming is faster and easier if you know the drill.

1 comment:

  1. I am SO glad I am not trying to do this in the water right now. Doing it on the boat after pulling the engine is tough enough!