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2005 Tohatsu 5hp MFS5A 4 stroke water pipe repair

Encee

New member
Went to change the impeller on my 2005 Tohatsu 5hp 4 stroke that I bought used and while I was removing the lower unit the water pipe was stuck in the water pump rubber grommet snugly and in the process the water pipe snapped in a couple of places due to corrosion (about 10” above the water pump and at the elbow at the top where it goes to the housing). Most likely the impeller had not been changed for a long time and the rubber grommet didn’t release the water pipe as the rubber has become hardened. The water pipe ultimately came out of the grommet with only a slight pull, but is now split in two rendering it useless.

A few questions regarding the repair.. after reading the Service Manual it looks like I will have to pull the Power Unit in order to gain access to the water pipe, is this correct? Is this a common issue with these outboards that are used in saltwater and do I need to consider any other maintenance when attempting this repair? Also, is it worth making the repair or does this level of corrosion indicate bigger issues?

The outboard was running fine and starting on the first or second pull always. I used it a handful of times with no issues and the impeller change was just to perform general maintenance. I will upload a photo if I can figure it out. Thanks in advance.
 
I have been unsuccessful in trying to edit my original post or upload a photo. To clarify the part in question is;

WATER PIPE "S"
369651000

Its the approximately 19” long pipe that goes from the water pump outlet up the drive shaft housing.
 
Not what you want to hear.----But I never run into this " hard to repair " issue on older domestic products.----Perhaps consider making the water pipe from stainless tubing.
 
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Not what you want to hear.----But I never run into this " hard to repair " issue on older domestic products.----Perhaps consider making the water pipe from stainless tuning.

I plan to replace with the OEM part with the intent of flushing each time after using in salt water, so my concern isn’t the durability as much as making sure the correct procedure here is to remove the Power Unit in order to feed the new Water Tube down the Drive Shaft housing.

I’m also curious if anybody knows or can suggest any other items I should consider repairing, if I end up proceeding with the repair & while I have the Power Unit pulled.

Lastly, just trying to determine if this is worth proceeding with or if this indicates a bigger corrosion issue rendering the repair nothing more than a bandaid type of fix. I’m not an expert marine mechanic by any means and would like to
understand better.

Guess I’m unlucky in my used purchase if this isn’t a common problem resulting in a ‘hard to repair’ issue.
 
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369651000MWATER PIPE S$18.75

Yes, you need to pull the power head. No, it is not indicative of other issues, except the motor may not have been flushed... or tilted up... frequently.
On the Great Lakes, we do that job about every 3 years... Cold, clear non salt water, and a short season. I always do the complete wp kit, as it's minimal extra expense for parts, and the same labor.
Never seen a water pipe so stuck that it broke. Ever.
You will need some gasketing and patience, but it should be a relatively quick job.
 
369651000MWATER PIPE S$18.75

Yes, you need to pull the power head. No, it is not indicative of other issues, except the motor may not have been flushed... or tilted up... frequently.
On the Great Lakes, we do that job about every 3 years... Cold, clear non salt water, and a short season. I always do the complete wp kit, as it's minimal extra expense for parts, and the same labor.
Never seen a water pipe so stuck that it broke. Ever.
You will need some gasketing and patience, but it should be a relatively quick job.

Thanks for the tips and the part #. I’ll take the dive and get the problem corrected.
 
Thanks for the tips and the part #. I’ll take the dive and get the problem corrected.

Reporting back.. mission complete. Took a little persuasion to separate the power unit for the housing, but once that was off it was just a matter of cleaning the mating surfaces for the new gasket. The water pipe indeed was corroded by salt, so I did what I could do to clean up the surfaces & the new waterpipe slid right in as expected. Rebuild the pump, new impeller and rubber grommets for the impeller housing and the pee stream is like a jet now. Started up first pull. Thanks again for the info.
 
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