Easy Impellar Job on 8.1's

Hampton

Hampton

Air Defense Dept
TECHNICAL Contributor
Nov 26, 2006
7,628
Panama City, Fl
Boat Info
2008 44 Sedan Bridge
Engines
Cummins QSC-500's
Straight Drives
The dealer wants at least 6 hours labor on these - 2 Impellar replacements on 8.1's on 2005 340. I dove into the job today. I started on the stbd because it was easier to get at. 2 nuts to loosen the belt, no obstructions - easy off. 2 nuts and one bolt on the bracket, all facing forward (stern of boat as the engines are in backwards) - no obstructions - easy off. 2 hose clamps - easy. 1 sensor plug - 10 seconds. Lower, positive pressure hose - a couple of minutes each, but not too easy. 2 water drain fittings - 1 minute each.

Stbd negative pressure, reinforced hose - 45 minutes. This booger was tough!!!!!!!!!!!!!!!!!!!! The pump was hanging on the two protruding bolts that the bracket was attached to, so, as I pulled the pump away from the negative pressure hose (intake, vacuum), the bolts limited the mobility of the pump. I couldn't twist and turn it. I had to pull it straight out, then coax a screwdriver in around the hose. Only 1/4 of it was accessible due to the rest being blocked by the pump. I finally got it off by putting a socket driver handle between the pump and the engine block after pulling it out away from the block in line with the bolts that hold the bracket. That gave me a little leverage to twist the pump and get the hose to let loose.

The hose is rock solid, and only 18" long. Since the pump is slid on to the two, long bracket bolts, you have to pull it straight out to get the hose off - it isn't easy.

Then, I attacked the port side. It is less accessible. I had to lay down behind the muffler and do the work with my arms stretched out and wrapped around the muffler. The whole job took 20 minutes - that's all! The Port hoses released the pump easily. They must have been off before.

The damn impellars that I bought in Miami for my trip home had the wrong sized hubs, so I had to go to the dealer and buy two new ones. In the mean time, I took one of the brackets home, cleaned it with a wire brush, then re-painted it - it had rust spots. I guess I'm keeping this boat a while. Doing a job like this on a bracket is dedication.

I'll put it all back together tomorrow after work. I'll report back then.

First impression - the negative pressure hoses are a bear, but the whole job is not worth $800. Take your wrench out, and go do it yourself.
 
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Thanks - These guys have a monopoly, and they know it.
 
I finished the job this afternoon. I can't imagine doing this job for 100 each. I wouldn't pay 800 either. It took about 2.5 hours to put it all back together, prime the pumps, start 'em up and then clean up. It was nearly 6 hours for an amateur, taking my time, cleaning stuff up as I went.

You guys know that these are inboards with V-drives, right?
 
Hampton said:
I finished the job this afternoon. I can't imagine doing this job for 100 each. I wouldn't pay 800 either. It took about 2.5 hours to put it all back together, prime the pumps, start 'em up and then clean up. It was nearly 6 hours for an amateur, taking my time, cleaning stuff up as I went.

You guys know that these are inboards with V-drives, right?
Click to expand...
I know, i'm giggling a little. I do about 50 of those a yr. Can get an engine dine in about 1 hr.
 
An hour? I could too, if it was sitting on a stand in my garage.
 
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Hampton wrote I had to lay down behind the muffler

"How big an ole boy are you" that you can lay down in the engine compartment of a 340 with 8.1s? Next time have someone take a picture.
 
Ha! Now you know why I do my own work. I'm 5'6" on a good day, and not too overweight, unless you count the donut (minor beer belly?). I was asking who they had to get in there and perform a lot of this maintenance. They said they had to find the smallest guy that was flexible, and had some working knowledge of engines. I thought, "Hey, that's me." So, I do my own work, to an extent.
 
We got a fellow like you at our marina...."hey Tang, can you help me for a second"....my 6'4" frame has its advantages....lifting, pulling, carrying, hanging on, propping 600hp Stearmans back in my youth.
 
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i just did my stbd engine. 7.4s (not 8.1s) but probably similar, and definitely just as costly. my buddy with fuel injected (newer) 7.4s (i think he has a serpentine belt, i have individual belts) just paid our marina $700+.

in aug of 05 i had our place do the port engine and they banged me for $350 and i gave them the impeller (i had bought it thinking i could handle the job, but didnt even know where to begin).

after asking around and bugging my other buddy jon to walk me through the process, i got it done. it took about 1.5 hours to get the pump out (mostly b/c i dropped the wrench under the *&$% engine and it took 40 minutes to retrieve it), 30 minutes to pop the new impeller into the new housing, and another hour to reinstall the pump and the new belts.

i will concede that this is a backbreaking job merely because of access (or lack there-of). i literally stood on my head or straddled the engine and leaned over the front of it, and spent quite a bit of time in these positions. but i am CERTAIN it is not as complicated for someone who does it frequently (ie: your friendly neighborhood marine mechanic).

is that a solid impeller on the 8.1s? mine is a rubber paddlewheel type. i know that crusader uses stainless impellers.
 
Thanks for the affirmation, guys. It's a rubber paddlewheel. Your times look very similar to mine. I dropped a couple of things - sockets, rubber gaskets to the drain ports... I also stripped, cleaned, and re-painted one of the pulley brackets. Mine have serpentine belts.

I just feel really good about getting in there and doing the job. In the mean time, I cleaned stuff up that needed attention - stuff that would not have had attention for $800.
 
it is certainly gratifying and satisfying to do it yourself, and it's even better to "STICK IT TO DA MAN!!"
 
Just spent 3 hours replacing the port impeller. The starboard impeller looks much easier. Probably 1 hour or so. The access to the port pump hoses was very difficult.
My mechanic gets $100./hr so I saved $400. in labor. We pay $3.00 for gas and average probably 20 gal./hr. on the water. You can be sure that I am really going to enjoy the next 7 hours on the water.
Boating ain't dead around here by a long shot .
 
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I have easy access to these pumps on both my engines (forward facing engines with straight shafts). There is also plenty of room to sit directly in front of the engines.

Is it necessary to remove the entire unit, hoses and all - or is it possible to just remove the front housing (from the pulley to the rear part of the casing) and expose the impellar for replacement? :huh:

I haven't taken a real close look at it but I remember seeing 3 or 4 bolts that seem to hold the two halves of the pump together. From this report it sure sounds like taking the hoses off is the most labour, so if it can be avoided that would be great! :thumbsup:
 
Hampton said:
I finished the job this afternoon. I can't imagine doing this job for 100 each. I wouldn't pay 800 either. It took about 2.5 hours to put it all back together, prime the pumps, start 'em up and then clean up. It was nearly 6 hours for an amateur, taking my time, cleaning stuff up as I went.

You guys know that these are inboards with V-drives, right?
Click to expand...

John,

What did you do to "prime the pumps" other than coat the impellers with dishwashing detergent and "crank 'em up"?
 
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