Replacement of Tilt Tube in 1989 Mercury 150

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Author Topic:   Replacement of Tilt Tube in 1989 Mercury 150

Tom W Clark posted 05-07-2008 09:20 PM ET (US)
I have two 1989 Mercury 150s on my Revenge 25. They run well and I have no plans to replace them. However, like many outboards of this vintage, there are important parts that were not made of stainless steel back then. Parts that in outboards made today are made of stainless steel. In particular, the tilt tubes on these motors are not stainless steel and they have rusted a great deal over the last 19 years.
I would like to replace the tilt tubes on these motors and even have the new stainless steel tilt tubes in hand. I have discussed the operation with my mechanic and he discouraged me from even trying. He does not think they will come out easily if at all. He even said he has a special tool for extracting them and it may or may not work.
I do not accept this. I am sure it can be done...somehow and would like any useful advice from those who have gone through this.
One of the problems is that the motor will have to come off the transom; the transom notch is not wide enough to allow the tubes to be extracted without interference.
If I can get the motors off the transom, how should I go about getting the tubes out? I am think of some sort of destructive method, cutting/grinding them out. The pressure of the expanding rust must be relived. How should I go about doing that?
Thought? Ideas?
sosmerc posted 05-07-2008 10:39 PM ET (US)
I have done this job a number of times in the past. Here's what I do:
Remove the engines from the boat and have the motor hanging from either my chain hoist or my motor toter.
I first remove both the port and startboard brackets. Most likely you will require some heat. I use an oxy/acetylene torch for heat. I heat the aluminum evenly and carefully around the tube. I leave one of the tilt tube nuts on and use a large breaker bar and socket and try and get the tube rotating. Once you get it to rotate freely then you should be able to pound it out. Don't bother pounding until you can get it to rotate.
Be sure to clean the area all around where you are going to be heating so that you don't start a fire from the grease/oil/gas that generally covers the area. Be careful not to heat or burn the power trim wires.
sosmerc posted 05-08-2008 12:52 AM ET (US)
One other sugguestion I forgot to mention. The zirc fitting at the front of the engine lubes the tilt tube so as to make it easier for the engine to pivot on the tube.
Before you remove the engine from the boat, see if you can feed grease through this zirc while trimming the engine up and down. If you are able to work some grease into this area, it will make it much easier to remove the tube. The transom brackets may present more of a problem as they are not lubed via a zirc. That's why I remove them first. Using heat and then rotating the brackets generally loosens things up and then it gets easy. Not all that much beating required if you are skillful with the heat.
L H G posted 05-08-2008 06:17 PM ET (US)
I have removed and reversed the tilt tubes on several of my Mercs, in my case for the purpose of installing the side mount hydraulic steering cylinders and putting on the Steersman grease nut. For me, it is an incredibly simple job, since both my 115's and 200's are on brakets, which gives clear path for sliding the tilt tube out.
Here's how I do it (with engine on the boat), and how they showed me how to do it at Sundance Marine in Ft Lauderdale:
1. Take SOS's advice of using the tilt tube grease zerk to be sure the tilt tube and engine tilt-up are well lubed.
2. Trim the engine vertical and place blocking just finger tight under the skeg so the engine can't drop or move.
3. (this is the hardest part of the job) Using two correct size wrenches, break loose the two painted-in nuts holding the tilt tube in place. The nut on the port side does not even have to come off completely. Doing this will also get the tilt tube turning freely. I also recommend having brand new replacement SS nuts on hand from Mercury.
4. Drive the old tilt tube out USING THE NEW TILT TUBE, and keep tapping the new one in until it is perfectly positioned. Install new nuts and tighten. You're done.
This method does not disturb any of the hardware (gaskets, washers, etc) in the tilt tube, and no time is the engine not fully supported on the tubes. Once you get the old nuts off, this is a simple task. I have done it about 5 times.
If the engine has to come off the boat, I would recommend bolting it on to a solid engine stand or dealer's engine rack, and u sing same method.
If one of the engines does not have any steering gear in the tilt tube, I recommend closing off the open ends with bait well plugs, to keep it clean inside.
Tom W Clark posted 05-08-2008 06:33 PM ET (US)
Steve,
Thanks for the good advice. What is involved in getting the port and starboard brackets off?
Larry,
Thanks for the description; I have read your accounts before but this will obviously do me no good as my tubes are very rusted and the transom notch precludes doing anything with them while the motors are still on the transom.
sosmerc posted 05-09-2008 01:03 AM ET (US)
There are 3 bolts with 5/8's heads on each side of the brackets. They secure the power trim system to the brackets. Remove them. Then remove the large nuts on either side of the tilt tubes...or at least one of them.
Where the tilt tube passes through the brackets may be tight. This is where you made to apply some heat. Rotating the tilt tube will help. Having the engine hanging from a chain hoist so that you can easily work at the front of the engine makes this easier than when mounted on a stand.
Removing the trim assembly is not necessary, but is not actually a bad idea as you can then lube up the pin that is the only thing left holding the trim system on the engine. It will make removing and servicing the trim system easier down the road when it eventually needs repair. If you actually have a trim sender on the engine that actually functions...good luck removing the two small blots that secure it. If the sender doesn't function, why not just remove it and be done with it. (I generally remove these whenever possible because they are such a piece of junk) Maybe the new digital units will hold up better. And perhaps someone actually spent an extra few seconds to put some anti-sieze or loctite on the bolts before assembly to prevent them from just breaking off down the road when things need service.:)
Tom W Clark posted 05-10-2008 10:50 PM ET (US)
Steve,
Thank you for the sound guidance. Now I just need to find a place to dangle my motors...

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Author	Topic: Replacement of Tilt Tube in 1989 Mercury 150
Tom W Clark	posted 05-07-2008 09:20 PM ET (US) I have two 1989 Mercury 150s on my Revenge 25. They run well and I have no plans to replace them. However, like many outboards of this vintage, there are important parts that were not made of stainless steel back then. Parts that in outboards made today are made of stainless steel. In particular, the tilt tubes on these motors are not stainless steel and they have rusted a great deal over the last 19 years. I would like to replace the tilt tubes on these motors and even have the new stainless steel tilt tubes in hand. I have discussed the operation with my mechanic and he discouraged me from even trying. He does not think they will come out easily if at all. He even said he has a special tool for extracting them and it may or may not work. I do not accept this. I am sure it can be done...somehow and would like any useful advice from those who have gone through this. One of the problems is that the motor will have to come off the transom; the transom notch is not wide enough to allow the tubes to be extracted without interference. If I can get the motors off the transom, how should I go about getting the tubes out? I am think of some sort of destructive method, cutting/grinding them out. The pressure of the expanding rust must be relived. How should I go about doing that? Thought? Ideas?
sosmerc	posted 05-07-2008 10:39 PM ET (US) I have done this job a number of times in the past. Here's what I do: Remove the engines from the boat and have the motor hanging from either my chain hoist or my motor toter. I first remove both the port and startboard brackets. Most likely you will require some heat. I use an oxy/acetylene torch for heat. I heat the aluminum evenly and carefully around the tube. I leave one of the tilt tube nuts on and use a large breaker bar and socket and try and get the tube rotating. Once you get it to rotate freely then you should be able to pound it out. Don't bother pounding until you can get it to rotate. Be sure to clean the area all around where you are going to be heating so that you don't start a fire from the grease/oil/gas that generally covers the area. Be careful not to heat or burn the power trim wires.
sosmerc	posted 05-08-2008 12:52 AM ET (US) One other sugguestion I forgot to mention. The zirc fitting at the front of the engine lubes the tilt tube so as to make it easier for the engine to pivot on the tube. Before you remove the engine from the boat, see if you can feed grease through this zirc while trimming the engine up and down. If you are able to work some grease into this area, it will make it much easier to remove the tube. The transom brackets may present more of a problem as they are not lubed via a zirc. That's why I remove them first. Using heat and then rotating the brackets generally loosens things up and then it gets easy. Not all that much beating required if you are skillful with the heat.
L H G	posted 05-08-2008 06:17 PM ET (US) I have removed and reversed the tilt tubes on several of my Mercs, in my case for the purpose of installing the side mount hydraulic steering cylinders and putting on the Steersman grease nut. For me, it is an incredibly simple job, since both my 115's and 200's are on brakets, which gives clear path for sliding the tilt tube out. Here's how I do it (with engine on the boat), and how they showed me how to do it at Sundance Marine in Ft Lauderdale: 1. Take SOS's advice of using the tilt tube grease zerk to be sure the tilt tube and engine tilt-up are well lubed. 2. Trim the engine vertical and place blocking just finger tight under the skeg so the engine can't drop or move. 3. (this is the hardest part of the job) Using two correct size wrenches, break loose the two painted-in nuts holding the tilt tube in place. The nut on the port side does not even have to come off completely. Doing this will also get the tilt tube turning freely. I also recommend having brand new replacement SS nuts on hand from Mercury. 4. Drive the old tilt tube out USING THE NEW TILT TUBE, and keep tapping the new one in until it is perfectly positioned. Install new nuts and tighten. You're done. This method does not disturb any of the hardware (gaskets, washers, etc) in the tilt tube, and no time is the engine not fully supported on the tubes. Once you get the old nuts off, this is a simple task. I have done it about 5 times. If the engine has to come off the boat, I would recommend bolting it on to a solid engine stand or dealer's engine rack, and u sing same method. If one of the engines does not have any steering gear in the tilt tube, I recommend closing off the open ends with bait well plugs, to keep it clean inside.
Tom W Clark	posted 05-08-2008 06:33 PM ET (US) Steve, Thanks for the good advice. What is involved in getting the port and starboard brackets off? Larry, Thanks for the description; I have read your accounts before but this will obviously do me no good as my tubes are very rusted and the transom notch precludes doing anything with them while the motors are still on the transom.
sosmerc	posted 05-09-2008 01:03 AM ET (US) There are 3 bolts with 5/8's heads on each side of the brackets. They secure the power trim system to the brackets. Remove them. Then remove the large nuts on either side of the tilt tubes...or at least one of them. Where the tilt tube passes through the brackets may be tight. This is where you made to apply some heat. Rotating the tilt tube will help. Having the engine hanging from a chain hoist so that you can easily work at the front of the engine makes this easier than when mounted on a stand. Removing the trim assembly is not necessary, but is not actually a bad idea as you can then lube up the pin that is the only thing left holding the trim system on the engine. It will make removing and servicing the trim system easier down the road when it eventually needs repair. If you actually have a trim sender on the engine that actually functions...good luck removing the two small blots that secure it. If the sender doesn't function, why not just remove it and be done with it. (I generally remove these whenever possible because they are such a piece of junk) Maybe the new digital units will hold up better. And perhaps someone actually spent an extra few seconds to put some anti-sieze or loctite on the bolts before assembly to prevent them from just breaking off down the road when things need service.:)
Tom W Clark	posted 05-10-2008 10:50 PM ET (US) Steve, Thank you for the sound guidance. Now I just need to find a place to dangle my motors...