8.1L Mercury Horizon impeller?

Anyone know the part number for an impeller on a 09' 8.1L Mercury Horizon in my Epic?

I know most people change there's out every year but I haven't done mine yet. I was out last weekend and it started to get hot at idle. It was fine while running though. I figured it wasn't getting enough water at the lower rpm.

Thanks

Hi Joe; Looks like the Epic owners are laying low right now....LOL After several impellers I had to change the complete pump assembly on my '09 Epic last month. (bearings were bad) Here is a web page with part numbers and a diagram. It is not a fun job!! BTW...We are at 715 hours and still loving ours.

http://goo.gl/BE96AJ

Thanks for the link.

You know how it goes. One turd in the punch bowl wrecks the whole party. I don't have nearly as many hours yet, but I love mine too.

Does it have the plastic impeller housing?

Slightly different housing(the plastic one) but same procedure - https://www.youtube.com/watch?v=UxLfF2abE_o I've done several... Not fun but once you do one the next one is easier Good Luck with it!

Let us know how it goes Joe...

LanceM

How do you get to it? It's at the deepest, darkest, bottom corner of the engine, covered by hoses and wires... is there a secrete to getting to it easily?

Yeah, I thought the same thing. I wish the engineers that design stuff would have to work on it themselves. They could've easily put it in an easier spot.

I ordered the parts today. Hopefully the housing isn't cracked because I didn't order that.

I'll kept you guys posted. Thanks for the link and the video!

Some of our really early boats are different but in most cases you pull the side engine panel out and lay on the floor to get under there... I don't remember it being particularly difficult to get to any of the bolts with a bit of arm contortionism

That's exactly how I have done mine Chris. I did find that it was much easier to remove the exhaust on that side. (easily done) On mine the parts numbered 8 through 13 (on the diagram in the link in my previous post) stay mounted to the engine. The remainder need to be removed to access the impeller. It's not as difficult as it appears.

I did this repair last weekend, and boy was it fun!! Ok, it wasn't that much fun... but this is how I did mine.

We first took off the belt and looked at the motor and diagram, and discovered my seawater pump resembled this diagram better than the one previously provided: http://www.boats.net/parts/search/Me...ump/parts.html


Not a big difference, but it makes me more sure of myself when I do not have any discrepancies between what I see in the diagram and what I see (and sometimes only feel) in the real life.

We took a note from Dale and removed the exhaust muffler - I highly recommend this! IT may not be necessary, but for anyone new to the motor, it is a valuable exercise. It provides so much more access. With the muffler removed, I could practically lie across the motor and hang down to the pump. This position in combination of lying in the two rear lockers provided much more access than I thought we were going to have. Next we removed the horizontal pump bolt (14 in the diagram), and then removed both "21" bolts... which were the wrong bolts!! Oops... no worries... they went back in without issues. Then we removed the right bolts - all 5 bolts that you can see of the 6 that connect the two sides of "1" (the pump housing) to each other. Then the pump housing came off of the engine (it was held on by the middle bolt on the starboard side and the top bolt on the port side). Then we could access the 6th and final bolt that holds the impeller housing together (the top bolt on the starboard side). We then removed the pulley side of the pump housing. From there, it was pretty simple and strait-forward. I was surprised at how easy it was to finger tighten the bolts on the install, especially when compared to how I could not finger loosen the bolts on the dis-assembly.

Below is a picture of my shredded impeller, just for laughs... then two pictures of a burnt plastic thing we pulled from the starboard side exhaust tube - the top, horizontal 5" rubber hose. IT was just sitting in there. I have no idea what it was. I am pretty sure it wasn't supposed to be there. ;-) Any ideas?

Wow... That looks like alot of work... Glad you had some nice solid help!

Lance MOUNTAIN!

Originally Posted by LanceM

Wow... That looks like alot of work... Glad you had some nice solid help!

Lance MOUNTAIN!

It makes all the difference!!

Blah!

I got my parts this week. I even got so far as crawling in the locker, taking one look, and deciding it was a good job for another day.

Good work Things do get nasty in those pumps when the rubber goes! No clue on the burnt plastic... But, at least its out!

No clue on the burnt plastic... But, at least its out!

I removed the exhausts on both sides. One side had the deformed burnt plastic as in Chris's picture, the other side was still intact. It appears that they are round discs installed midway in the length of the exhaust hose to maintain the structural integrity of the hose. (For years I had wondered why there were hose clamps midway on the hoses for no apparent reason. Now I know that they were holding these discs in position) They both went in the trash.....don't need 'em.

http://www.marinemechanic.com/merc/d...erinengine.PDF

Those are actually resonators. Some systems need them to prevent buildup of water in the exhaust manifolds. A lot of builders used them just to be safe. Be aware that under certain situations they may be needed to prevent exhaust reversion from getting into your motor.

Why they were made of plastic is a mystery to me, we see a lot of them just like the photos from relatively mild overheats.

If you decide you want to replace them, the Mercury part number is 860222A1, about 40 bucks per side.

Originally Posted by meathead65

http://www.marinemechanic.com/merc/d...erinengine.PDF

Those are actually resonators. Some systems need them to prevent buildup of water in the exhaust manifolds. A lot of builders used them just to be safe. Be aware that under certain situations they may be needed to prevent exhaust reversion from getting into your motor.

Why they were made of plastic is a mystery to me, we see a lot of them just like the photos from relatively mild overheats.

If you decide you want to replace them, the Mercury part number is 860222A1, about 40 bucks per side.

meathead for the win! Thanks! That solves the "WTF IS THAT!" question...

Here is what I believe to be the relevant section of the link:

6. Boat exhaust systems (engines with thru-hull exhaust only).
a. Engines with thru-hull exhaust systems can have a ‘tuning’ effect. Exhaust hose
length, 45
, or 90
fittings, location of collector and/or muffler and the thru-hull exhaust
tip all can affect water ingestion. The only way to test for this condition is to
monitor the amount of water that collects in the runners of the exhaust manifold after
idling for 45 minutes. Engine has to be at normal operating temperature before starting
the idle test. Using Exhaust Resonator Kits in the exhaust hoses will help stop
the ‘tuning’ affect in the exhaust system. The Mercury Parts Exhaust Resonator Kit
does not cause any horsepower loss.

What does it mean by a "tuning effect?" In a quick google search... it looks like this is some what of a siphoning effect? I see a lot of references like, "Special care must be taken on through the hull exhaust applications, as the design of these systems can produce a tuning effect
that can cause water to be pulled back into the engine." I am obviously not an expert, but I don't see how this piece of plastic helps to prevent water from being pulled back into the engine. Can you explain it? (speak in simple words and I should understand lol)

I'm just a old boat wrench, and some of the technical reasons for tuning effect are out of my area of expertise. I have in the past understood it to be a "perfect storm" situation whereas the design and layout of the exhaust system can create a low pressure vacuum effect at some particular RPM, typically when the boat is moving at idle or low speed off plane speeds. The venturi effect of the exhaust outlets below waterline combined with the exhaust pulses in these systems can lead to water being drawn back into the system. My guess is that the resonators by design create a disturbance in the exhaust water and gas flow out of the system to upset these pulses, cancelling out "tuning effect".

I believe these resonators are most common on late model, high horsepower big blocks that have a substantial amount of valve overlap, increasing the chance of setting up the reversion situation.