Author Topic: The T-166XL Sporster Deluxe Rebuild (Code Name: Plan ~ B)  (Read 74193 times)

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Offline still_fishin

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Re: The T-166XL Sporster Deluxe Rebuild (Code Name: Plan ~ B)
« Reply #220 on: May 12, 2017, 09:12:00 PM »
Did some reading on iboats, and found that exhaust and head gaskets could be a problem. Apparently there is some type of exhaust plate that commonly warps due to heat. Might look into that. I am not an outboard mechanic, so this is frustrating.

Literally dealing with this very same this on my fishing boat.  I just upgraded to a 1977 70hp Johnson from a 1979 55hp Johnson.  A long story short  I ended up with water in the bottom cylinder.  I got it home and started striping parts off it.  I figured it was the head, nope. Anything after the head you have to get creative or just pull the power head to get to the bolts, which is what I did. Get the harness out of the way,  same with the fuel,  remove the bolt connecting the linkage with the shift shaft under the bottom carb, the beauty cover under the lower cowl,  then the six bolts into the block and last the nut about 3" under the bottom spark plug. Remove power head,  start with pulling the  exhaust side.  It is probably the gasket closest to the power head,  that is where mine failed.  The complete gasket kit is $65 for Sierra or between $80 and $100 for oem on ebay.  I ordered the whole kit and will install all of them,  after all,  these seals are 40 years old, it is time. Have fun. 
« Last Edit: May 12, 2017, 09:17:46 PM by still_fishin »
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Offline dorelse

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Re: The T-166XL Sporster Deluxe Rebuild (Code Name: Plan ~ B)
« Reply #221 on: May 12, 2017, 11:06:04 PM »
On the positive side Brian...you had a boat in the water!  How good did that feel?
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Offline still_fishin

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Re: The T-166XL Sporster Deluxe Rebuild (Code Name: Plan ~ B)
« Reply #222 on: May 16, 2017, 04:21:04 PM »
Literally dealing with this very same this on my fishing boat.  I just upgraded to a 1977 70hp Johnson from a 1979 55hp Johnson.  A long story short  I ended up with water in the bottom cylinder.  I got it home and started striping parts off it.  I figured it was the head, nope. Anything after the head you have to get creative or just pull the power head to get to the bolts, which is what I did. Get the harness out of the way,  same with the fuel,  remove the bolt connecting the linkage with the shift shaft under the bottom carb, the beauty cover under the lower cowl,  then the six bolts into the block and last the nut about 3" under the bottom spark plug. Remove power head,  start with pulling the  exhaust side.  It is probably the gasket closest to the power head,  that is where mine failed.  The complete gasket kit is $65 for Sierra or between $80 and $100 for oem on ebay.  I ordered the whole kit and will install all of them,  after all,  these seals are 40 years old, it is time. Have fun.

I finished mine up yesterday. I replaced all the seals that I couldn't get to with out pulling the power head again (leaving only the gaskets for cooling the head). I haven't had it in the water yet but did pop it off in the garage, seems to run the same as it did before the gasket failure. My only advice is to make sure the upper main bearing stays in place.  I separated my block 5 or 6 times trying to figure out why the rotating assembly was binding.  Figured out the upper main bearing was positioned a little to low.  Non of this project was too difficult with the right tools.  Mainly an engine hoist.
I'm done,  sorry for the hijack.   
Oh,  and I wouldn't let that engine sit for too long with out oiling down that cylinder. 
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Offline porterra

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Re: The T-166XL Sporster Deluxe Rebuild (Code Name: Plan ~ B)
« Reply #223 on: November 24, 2018, 07:17:35 PM »
Hey Brian,  were you able to get it out?   Sitting here with. Y father in law  for Thanksgiving and I got thinking about the boat.