How often should Impellers be replaced

Bullet: of course you are correct. They install all the stuff before the deck goes on. How do you argue with makers that say buyers want every possible inch of interior living and storage space instead of acess. Staying under warantee coverage where someone else is responsable for work is a reason some people trade every few years. Guess who benefits from that.
 
quote:
Originally posted by pdecat

Bullet: of course you are correct. They install all the stuff before the deck goes on. How do you argue with makers that say buyers want every possible inch of interior living and storage space instead of acess. Staying under warantee coverage where someone else is responsable for work is a reason some people trade every few years. Guess who benefits from that.

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I agree. Sure, it would be nice for someone to do a ground-up re-engineering of an inboard motor, but would consumers be willing to pay an extra $15,000 per engine? Would boat builders be willing to take that risk? In order to take advantage of such a re-engineered powerplant the boat would need to be designed around it. Personally, I want to see Suzuki or Honda or Yamaha tackle the inboard and inboard/outboard market. Maybe it will happen as those little jet boats (which are themselves overgrown jetskis) continue to grow into cruisers.
 
pdecat, glad you agree! I've been in this business for lot's of years and not too much has changed. Sometimes, I still have to use an 18" extension on a 3/8 ratchet to get to a bolt that then falls into the lowest part of the bilge. Sure, stainless bolts are great but my magnet won't work? I like the warranty covered boats and engines though, they have to fix it! Then, I just sit at the dock and watch. I usually watch and learn a little bit more. This boating thing is still better than that daily commute and that office/desk thing!
 
crillo: for one simple example mercruiser design their own bell housings why not mount the starter there instead of under the engine???
 
i think that Merc just has a history of not making things easy on owners. I'm not saying it's a conspiracy to help it's dealers but you got to wonder.

Isn't the Alpha one the only stern drive with the raw water pump in the outdrive ? which means that if you need to change the impeller, you got to haul the boat out and open the drive.

i had a volvo sterndrive 280 of similar vintage (mid 80s).. the raw water pump was mounted on the front of the engine, a little low but still accessible, and replacing the impeller was a 10 minute job. remove the cover, pull the impeller, new impeller on, new gasket and cover on. could be down out on the water if you had to.

fast forward 13 years, mercruisers 7.4 inboards. the pump was no longer bronze but plastic... it had to be removed to replace the impeller, which means the serpentine belt had to come off. then they place the water hose behind the pump, making it almost impossible to remove one of them. which means you had to disconnect the other side of the hose (on the strainer) and route out from under the engine.

dont' tell me ie woudl take %15k more to use a proven bronze pump like most engine use !!

how about boats that will sink if the fragile main bellow gets a hole ? how thoughtful is that ! in the 13 years i owned that old 85 vintage volvo, i dont' even remember how many times i pulled the drive and found the bellow filled with water ! tear, hole, brken clamp... never got a drop inside the boat ! Volvo used a very good set of seals and bearing in the bellhousing with a grease fitting inside the boat.

sorry... i dind't mean to turn this thread into a volvo vs merc debate but when i read things like it woudl cost %15k more to do it right.. it really gets to me when boaters accept lousy designs...

oh one more... steel bolts on manifolds... after 3 or 4 years, you have to cut them since the heads have decomposed... if their dealers know to replace them with SS.. why cant' they ? save $3 ?

then we hear things like.. it's under warranty so i dont care. yeah.. right... and you dont' pay for the warranty when you buy an engine ? do you like waiting 2 or 3 weeks for the dealer to do the warranty work ? manifold and impellers are not warranty itmes anyway... so you are paying that full hour of labor to replace a merc impeller instead of spending 10 mnutes of your own time.
 
We could keep this thing going and going. Yamaha, who makes a great Outboard was doing the stern drive thing in the late 80's and early 90's, I guess they just couldn't compete with the Brunswick/Mercury Marine and Volvo/Penta. Their units, automotive based conversions, didn't have anything new on them. Maybe the Volvo/Penta had a better idea, service wise. They never put the raw water pump underwater in the sterndrive. The newer Merc Bluewater inboards at least put the starter on top of the bellhousing, out of the bilgewater. I guess for a few grand you do your own re-engineering. Remote mount the oil filters, install additional sensors for water pressure. Spend more time on fall lay-up and spring commissioning or maybe we should just use them more. I've found the ones that get more real engine hours on them, seem to be more trouble free. I have seen the one's that sit in the dock have trouble while the ones that are always running to somewhere, don't fail as often and when they do, the owners aren't nearly as upset.
 
I replace my water pump impeller every two years. Of course it is a Volvo and is easy to get to.

Pascal, you don't want to use stainless steel manifold bolts...to much stretch.
 
Nice rant Pascal!

The yamaha OD was a very pretty drive. Too bad they copied volvo a little too closely. They could very well have been at the top of the market by now.
 
The impellers will last longer in boats used year around than those which are laid up during the winter. As noted above, when the impellors are sitting, they take a set, and the vanes become more brittle, then tend to break a vane. I don't let them go more than 3 years, even with year around use.
 
Another reason for Yamaha's I/O demise was they were sharing factory space with OMC. Separate production areas, that was a good thing. Well, we all know what happened to OMC. I guess Yamaha didn't think it was worth it to keep that part of their market alive.
 
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