98 4.3 Mercruiser Engine Removal Advice

lintmann

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Apr 26, 2023
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The boat is a 99, the engine I believe is a 98. The engine stamp pad shows T06109LJ and it has what I believe is a Alpha 1 Gen 2 outdrive. I have a Mercury Service Manual that came with the boat and it's dated 99 so I assume it's current for this boat.

My question is, is it as straight forward as the manual states because there looks to be a lot more to it than what the manual reads. I'm an auto and aircraft mechanic by trade but have never pulled a boat engine so I'll be taking this slow and cautiously so that I don't damage anything. Due to ceiling issues in my shop I'll be removing the heads in the boat first so I'll actually only be lifting the weight of the short block. I have already removed the outdrive.

Any advice, tips or general thoughts are appreciated. Thanks.
 

XjasonX

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Feb 5, 2023
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I just went through this on a nearly identical motor. Like you I’ve been in the auto trade for 10+ years. It’s pretty straightforward, mark everything, take clear photos from all sides. We ran into a few issues but nothing that wasn’t fixable or able to be researched. Be prepared for finding additional issues. Check your motor mount stringers before you reinstall, make sure the lags will torque. Clean all your connections you remove.

Why are you removing the engine?
 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
12,671
remove the outdrive first
take pictures of how everything was before you remove stuff for example brackets for the alternator and P/S pump, label which bolts went to what.
label wires for sensors, etc
set up a system for organizing parts, so you can keep lifters, pushrods, rocker arms organized for the cylinder from where they came
the more organized you are the better, and pix and diagrams help because you will forget stuff.
I have not had to pull an engine but I did a top engine overhaul and it went a lot easier because I had a way to organize all the parts and took pix.
 

Scott06

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Apr 20, 2014
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6,440
The boat is a 99, the engine I believe is a 98. The engine stamp pad shows T06109LJ and it has what I believe is a Alpha 1 Gen 2 outdrive. I have a Mercury Service Manual that came with the boat and it's dated 99 so I assume it's current for this boat.

My question is, is it as straight forward as the manual states because there looks to be a lot more to it than what the manual reads. I'm an auto and aircraft mechanic by trade but have never pulled a boat engine so I'll be taking this slow and cautiously so that I don't damage anything. Due to ceiling issues in my shop I'll be removing the heads in the boat first so I'll actually only be lifting the weight of the short block. I have already removed the outdrive.

Any advice, tips or general thoughts are appreciated. Thanks.
this is easier than removing an engine from a car with the exception of the height needed to pull. You can take the wheels off the trailer and roll it on the hubs if that gives you more height. Eventually you are going to re-install this or another engine? Would be good to figure out how you can get the engine with heads and manifolds in there that way you can test run the engine on the ground before you put it back in.

it is relatively simple.-

remove drive- make sure it is in forward. With gen 2 drive disconnect the speedo tube at drive
flywheel cover mounts and lag screws from side mounts
fuel hose
electrical at cannon plug, 12v +/- cables off starter and flywheel cover
take the shift plate off the exhaust and put it out of the way, same with throttle cable.
Power steering hoses off the cylinder, leave ps cooler attached to flyhweel cover/block

It took about an hour the first time. biggest issue will be if you cannot get rear mount bolts out .
 

lintmann

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Apr 26, 2023
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15
Well I think all I have left now is to lift the engine. I don't see anything around it and two bolts at the rear of the bell housing and two nuts at the front engine mount are off. I just have a few questions...

XjasonX, what are the "mount stringers", and "make sure the lags will torque" ? Are the lags the front mounts that use a large nut? One nut was tight and the other about half as much so now I wonder if something is going on...
I'm removing it because the block has a pretty good crack. I bought it from a friend and we knew it was cracked so so far, no surprises.

Scott06, I never thought about running it before I put it back in. That's good advice and I'll look into the logistics of that when it's time. You mentioned "lag screws from side mounts", sorry for a noob question but are these the ones that attach the engine front mounts to the hull? I took the big nut off each mount and this would leave the mount attached to the hull. Am I supposed to keep the whole mount with the engine?

Okay so now it is just a matter of deciding if I need to removed the mount from the hull and slide the engine forward or lift it over the two studs. Can it be done either way?

Thanks again.
 

stresspoint

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Sep 19, 2022
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1,045
my 4.3 practically jumps out of the boat by itself it come in and out so many times when i was sorting the boat.

with that said , the best option to removing the front mounts is to take the mounts off from the engine block, its 4 x 9/16 bolts each side. when you dump the motor in these bolts align quite easily if you start with the lower rear one.
some masking tape over the shims (springy looking things under rear mount)helps to stop them falling as you locate the bell housing..
wiring is plug and play and most can be done with the motor on the stand , 2 x 9/16 at the rear of the motor will allow you to unplug and set aside the big round connector plug for the wiring .

i found it easier to set the motor into the boat without exhausts , i have AM extractors type so i am guessing fitting of those OEM risers and would be much easier when the motor is in the boat as trying to align the Y pipe rubbers is a PIA with the motor on the crane. , that would be up to your discretion depending on the configuration of your boat and how accessible the bolts are.

that's about it , everything else is as you see it.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Well I think all I have left now is to lift the engine. I don't see anything around it and two bolts at the rear of the bell housing and two nuts at the front engine mount are off. I just have a few questions...

XjasonX, what are the "mount stringers", and "make sure the lags will torque" ? Are the lags the front mounts that use a large nut? One nut was tight and the other about half as much so now I wonder if something is going on...
I'm removing it because the block has a pretty good crack. I bought it from a friend and we knew it was cracked so so far, no surprises.

Scott06, I never thought about running it before I put it back in. That's good advice and I'll look into the logistics of that when it's time. You mentioned "lag screws from side mounts", sorry for a noob question but are these the ones that attach the engine front mounts to the hull? I took the big nut off each mount and this would leave the mount attached to the hull. Am I supposed to keep the whole mount with the engine?

Okay so now it is just a matter of deciding if I need to removed the mount from the hull and slide the engine forward or lift it over the two studs. Can it be done either way?

Thanks again.
your front mounts have adjustment screws thru the brackets, however lag bolts holding them to the stringer mounts. that block of wood that the lag bolts are driven into with a burp gun usually get rotten.
 

Scott06

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Scott06, I never thought about running it before I put it back in. That's good advice and I'll look into the logistics of that when it's time. You mentioned "lag screws from side mounts", sorry for a noob question but are these the ones that attach the engine front mounts to the hull? I took the big nut off each mount and this would leave the mount attached to the hull. Am I supposed to keep the whole mount with the engine?

Okay so now it is just a matter of deciding if I need to removed the mount from the hull and slide the engine forward or lift it over the two studs. Can it be done either way?

Thanks again.
Not sure what you are doing but I found it much easier to fully assemble and run on the ground. You can easily jumper out the cannon plug to test wiring harness etc then drop in the complete bob tail.

I personally found it easier to remove the two lag screws holding the mounts to the stringers, as soon as you take weight up the engine will move, pull it forward a bit to clear the steering and then up. Really dealer choice on the mounts. If your mounts are wood glassed into the stringers check them for rot before reinstalling the engine.
 

XjasonX

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Feb 5, 2023
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As others have sailed already, your engine mounts are attached to the boat likely through some type of stringer. They could be encapsulated by fiberglass over wood. If they rot out you will not be able to torque the bolts to the boat. Before you go through all the work of installing the motor just make sure that connection to the string that the engine sits on is able to be torqued proper.

While the engine is removed think about painting the Bilge. This depending on the type of paint you use can take days to harden correctly. If you have holes or any penetrations into the structure of the boat fill them with some 2 part epoxy.

With the engine removed it’s a good time to inspect and clean anything that’s not visible while it’s installed. For example, How old is the bilge pump? does the steering arm have play in the outdrive? do the lumber holes drain correctly? These are just some of the issues I faced with my removal, yours maybe different.

Do you have the alignment rod already?
 

lintmann

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Apr 26, 2023
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I was thinking that I should have a good look around when the engine is out but since I'm so new at this, I wasn't sure where to start. Thanks and I'll check those things for starters and do some searching here too.

What would be a typical torque for the lag bolts? I'm thinking I should see if they make torque now before I disturb anything else.

No I don't have an alignment tool yet.
 

XjasonX

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Feb 5, 2023
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From memory I believe it’s 35 ft lbs. mine were 3/8s lag bolts with the proper pilot hole drilled.
 

stresspoint

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Not sure what you are doing but I found it much easier to fully assemble and run on the ground. You can easily jumper out the cannon plug to test wiring harness etc then drop in the complete bob tail.

I personally found it easier to remove the two lag screws holding the mounts to the stringers, as soon as you take weight up the engine will move, pull it forward a bit to clear the steering and then up. Really dealer choice on the mounts. If your mounts are wood glassed into the stringers check them for rot before reinstalling the engine.
i personally have a thing when it comes to lag screws/bolts" let sleeping dogs lie' unless absolutely necessary to take them out IE: when parting a hull..
agreed .it is easier to remove the lag bolts " however 1 or 2 stripped threads when replacing is not an easy fix.
 

lintmann

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Apr 26, 2023
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15
Well it's out, no issues at all. I did try the lag bolts and was able to turn them maybe half a flat and they became quite tight so they should be okay. Thanks so much guys, I really appreciate all the advice.
 
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