242 limited pump questions.

[Utley]

I have a 2011 242 limited that I picked up a couple of weeks ago. The boat had sat in a slip and not been used too much. Jets had lots of corrosion on them. I am having some cavitation issues when you get on the power with it. You can feel the pumps slipping and kind of fighting to get traction if you know what I mean. From a dead stop taking off or when pulling a tube or wakeboarder they will especially slip and hit the rev limiter. Pulled the pumps apart and found corrosion on the bearing housing fins and on the first part of the pump that bolts to the hull. Lots of aluminum missing on that first ring right before the impeller. Could this be causing the cavitation, or should i be looking at the impeller more. Impeller condition is good, not much for dings, does look a little worn from sanding, though. Boat had 90 hours on it.

 

[Bennie]

I'm not as versed in this subject as @Bruce or @Julian but I would say that pump needs to be replaced.
ANYTHING other than smooth portals will cause undesired turbulence which will cause cavitation and the undesired performance effects that you are describing. I would look for new jets and definitely ensure that a new anode is put into place.

Where did the previous owner boat? Im guessing very poor maintenance after salt water use.

 

[Julian]

You want to focus your analysis on the impeller, impeller clearance, and forward of the impeller in the intake....those 3 areas will be your primary source of cavitation.

Looks to me like you have spots forward of the impeller that are in poor shape, and likely that your impeller clearance to the housing may have issues....but no shot of that...just a total guess

 

[Scottintexas]

@Utley glad to have you on board, update your profile with your location so we know where your at,

while the parts don't look very good at all I think that air intrusion is a bigger factor than rough edges.

It looks like your missing some silicone around the edges, reach up there and gently pull on it to see if any more is loose,

I would take the easy way first and just slap a layer of house hold silicone on all the mating edges and see if that fixes it, if it does you can come back later and put a longer lasting fix on it.

This is a thread on my cavitation problem https://jetboaters.net/threads/cavitation-missing-sealant-in-pump-grate.884/

Be sure to check out the FAQ for lots of great tips and especially make sure you oil cooler bolt hasn't broken off,

 

[Bruce]

How fast does she go? GPS based speed please. You can use that number to judge how efficient your pump is.

 

[davel501]

It is aluminum so you could pull it an polish it. More than likely, you need impellers and are missing the silicone at the front of the intake grates.

As Bruce mentioned, knowing your top speed will help but I am guessing that things are not nearly as bad as the dirt makes them look.

 

[Utley]

Top speed is about 48. Since these photos I resealed one of the pumps to see if that was the issue. No change. The pump I had apart I cleaned up and repainted it.

 

[Bruce]

Top speed is about 48. Since these photos I resealed one of the pumps to see if that was the issue. No change. The pump I had apart I cleaned up and repainted it.

Boattest shows a top speed of 51.4 on a new, unloaded boat so you are not missing much. http://www.boattest.com/review/yamaha/2057_242-limited-s

 

[Scottintexas]

they will especially slip and hit the rev limiter. //// Impeller condition is good, not much for dings, does look a little worn from sanding, though View attachment 41142View attachment 41141

If you think you have sufficiently replaced the sealant then I think I would check the impeller clearance next because I don't know how to fix all that corrosion forward of the impeller other than maybe covering with 4200 to smooth it out, I bet it would be a lot of money to buy those parts to replace,

You stated "They will slip and hit the rev limiter", do both tachs go to 10k when it slips or is it just one?

do you think the previous owner tried to do anything to fix it? just wondering if somebody screwed it up more or we're dealing with it from stock?

The sanding on the impeller, did you do that or it just appears to be sanded?

 

[Utley]

When it slips the left pump does first, then once that one does, the right one starts to.
As far as previous owner maintenance on this, I'm pretty sure nothing was tried on this. Looks like it slowly got worse over time and chances are he didn't really notice it was happening. I got the maintenance records for it from the dealership before I bought it and there's nothing to do with pumps on it. Sanding on the impellers I meant looks like wear from sand on it. I never physically sanded the impellers at all. What are the clearances supposed to be on the impeller? I can check that tonight. Thanks for all the help!

 

[Bruce]

This is a similar thread for comparison https://jetboaters.net/threads/what-do-you-think-about-my-port-impeller-and-pump-housing.9218/

This thread has clearance limits
https://jetboaters.net/threads/impeller-gap-010-good-or-bad.9484/

 

[waterboy]

The down flow side of the impeller is called the stator. It actually plays a very important role in the performance of the pump otherwise it wouldn't be there. Without it, the boat would probably just sit in place or not perform very well at all. In your pictures, the stator looks very worn. I would suspect this may play a key part in what you find also.

As others have said, yes the sealant is crucial to keep the pump from sucking air in and causing cavitation. The impeller clearance is also critical. The flow transition from the impeller to the stator is also extremely critical to get optimum performance from the pump. This transition is what directs the water flow towards the exit of the pump with the proper direction and velocity.

Some have talked about sanding these surfaces. Yes this will smooth out the surfaces, but guessing how critical these designs are to get proper flow dynamics, I would suspect that you may be in for the expensive replacement. Get a professional opinion on this though before spending the big bucks.

I don't know that my terms and description are completely accurate, just trying to relay how these type of water pumps operate. Hope that helps.

 

[davel501]

Looking at the parts on larger screen it looks like the cavitation has been eating away at the pump parts. You may very well be replacing a few parts.

 

[swatski]

Top speed is about 48. Since these photos I resealed one of the pumps to see if that was the issue. No change. The pump I had apart I cleaned up and repainted it.

I have a 2011 242 limited that I picked up a couple of weeks ago. The boat had sat in a slip and not been used too much. Jets had lots of corrosion on them. I am having some cavitation issues when you get on the power with it. You can feel the pumps slipping and kind of fighting to get traction if you know what I mean. From a dead stop taking off or when pulling a tube or wakeboarder they will especially slip and hit the rev limiter. Pulled the pumps apart and found corrosion on the bearing housing fins and on the first part of the pump that bolts to the hull. Lots of aluminum missing on that first ring right before the impeller. Could this be causing the cavitation, or should i be looking at the impeller more. Impeller condition is good, not much for dings, does look a little worn from sanding, though. Boat had 90 hours on it. View attachment 41142View attachment 41141

This is interesting. Would need more pics when you take it apart, but it is pretty clear you have a lot of corrosion of the transom plate (the first segment of the pump sealed to the transom). What's weird is that the top part of it appears okay, at least better that the bottom, suggesting it is primarily corrosion. You do have some cavitation burns as well, to be sure, but I would start with the transom plate.
Look, the parts in these pumps do not need to be smooth and shiny. That is a myth. Blasting and polishing these parts does basically NOTHING to top speed and acceleration. But, they all need to be sealed, and you need to have tight clearance of the impeller inside the wear ring. I would look into the threads that @Bruce posted up above for the specs, would be the fastest, its all there.

 

[davel501]

This is probably the sort of project that can wait until winter. 48mph is pretty good.

 

[swatski]

This is probably the sort of project that can wait until winter. 48mph is pretty good.

I would agree, 48mph is great, actually. That is, if it's consistent and is GPS based.
That said, if there is enough cavitation that you can feel it, and have issues pulling stuff, it would drive me completely crazy. I would be all over it, no doubt.

 

[davel501]

I would agree, 48mph is great, actually. That is, if it's consistent and is GPS based.
That said, if there is enough cavitation that you can feel it, and have issues pulling stuff, it would drive me completely crazy. I would be all over it, no doubt.

I agree but the season is probably about half done in North Dakota and parts can take a while to arrive.

 

[Utley]

That is what I was thinking on the impeller housing, the cavitation burns. Being the boat was in a slip, I'm assuming the way the pump was sitting in the water is where the corrosion is, that's why the top is fine. I do have good top speed, but like swatski said, it's gonna drive me nuts til I figure it out. I'd hate to fix all these parts in November and have to wait six months to see if I remedied it. I can get the parts pretty quick if needed. I'm planning on going out on Saturday, so for sure Saturday night I'll take a pump apart and measure the clearances, if not on Friday night if I get time. I got a really good deal on the boat, so putting some money into it doesn't make me feel too bad. I already had plans on replacing the transom plate on both and maybe the impeller bearing housings, but wasn't sure on the impellers. Definitely wanted some second opinions, and I got a lot of good ones! Thanks a lot guys for the good info, and I'll keep it updated on here what I find out.

 

[Utley]

Got anxious and decided to go measure the clearances. Pulled apart a pump and measured the clearances. The bottom and side is the most worn and I'm able to fit a .635mm feeler gauge in there. The top I'm able to fit .584 mm into that.

 

[swatski]

Got anxious and decided to go measure the clearances. Pulled apart a pump and measured the clearances. The bottom and side is the most worn and I'm able to fit a .635mm feeler gauge in there. The top I'm able to fit .584 mm into that.

That seems to be border line, or not bad at all! .014-.020 thousands inch or something close to that is the specfication any more than .025 thousands inch max and you speed and acceleration will suffer.