Mercruiser 3.0 - Replacing the Starter, What Else to Check?

morebacon

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I need to replace the starter on a Mercruiser 3.0L, so I'll be pulling the engine. What else should I be looking for / replacing?

I'm planning to do the gimbal bearing, bellows and water pump impeller as well.
 

alldodge

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Exhaust shutters and a compression and leak down test would let you know the health of the motor
 

achris

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.... What else should I be looking for / replacing?...

Look at everything, replace what needs to be replaced.

When doing any job, we do it with our eyes open, which means you just keep on the lookout for anything 'not right'. I see this 'tunnel vision' all the time. People start to do a job, like replacing spark plugs, and just 'don't see' the distributor cap that's cracked.... look at things through open eyes.

Chris......
 
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kenny nunez

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Also take a close look at the unpainted area on the timing cover that the harmonic balancer hides.
 

morebacon

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Exhaust shutters and a compression and leak down test would let you know the health of the motor

Thanks for the suggestion - compression looks good so far (165, 160, 165, 165), will check the rest.

Also take a close look at the unpainted area on the timing cover that the harmonic balancer hides.

Good point! I'm actually going to replace the timing cover completely, as it's leaking from the bottom where it meets the pan.

---

So I got the engine out over the weekend and also the gimbal bearing. How do I check if the gimbal is still serviceable? After cleaning it looks and feels pretty smooth, but it does have some surface rust.

Also split the outdrive and when turning the lower driveshaft it feels just a bit rough. From the parts diagram it looks like the roller bearing, how do I check if it's still good?
 

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achris

More fish than mountain goat
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Thanks for the suggestion - compression looks good so far (165, 160, 165, 165), will check the rest.



Good point! I'm actually going to replace the timing cover completely, as it's leaking from the bottom where it meets the pan.

---

So I got the engine out over the weekend and also the gimbal bearing. How do I check if the gimbal is still serviceable? After cleaning it looks and feels pretty smooth, but it does have some surface rust.

Once you take a gimbal bearing out, that's it, throw it in the dust bin... The mere act of removing it out damages the bearing race and ball surfaces... Buy a new one, watch my video and put the new one in. (click on the 'My Videos' link at the bottom of my signature and look for the video about gimbal bearings.)

Also split the outdrive and when turning the lower driveshaft it feels just a bit rough. From the parts diagram it looks like the roller bearing, how do I check if it's still good?

Depending on what the drive is, yes it will feel rough on the driveshaft bearing until you pull or push the shaft in the right direction. Drives before 1982 you need to push the drive shaft down, and drives 1982 and later, you need to pull it up to know how the bearing really feels.

Chris..........

EDIT: Looked at the photos, that's a gen II drive, so you need to pull up on the drive shaft. Also, that yoke looks water damaged. Was there water in the bellows when you pulled the drive?
 

morebacon

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Once you take a gimbal bearing out, that's it, throw it in the dust bin... The mere act of removing it out damages the bearing race and ball surfaces... Buy a new one, watch my video and put the new one in. (click on the 'My Videos' link at the bottom of my signature and look for the video about gimbal bearings.)

Thanks Chris, I actually had your videos bookmarked, very useful! :) I'm now having trouble driving the new gimbal back in. Tried freezing and pounding it in with a 3" pipe, as others have suggested, but no go. So I've ordered the proper tool to get it done, now waiting to get it delivered.

You need to pull up on the drive shaft. Also, that yoke looks water damaged. Was there water in the bellows when you pulled the drive?

Pulling it up worked! By doing that it feels smooth enough, so looks like we're good to go there. There was indeed some standing water in the bellows, but I didn't see any hole or anything. I'm replacing them anyways, as well as the shifter cable, which had the jacket cracked.
 

achris

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... I'm now having trouble driving the new gimbal back in. Tried freezing and pounding it in with a 3" pipe, as others have suggested, but no go. ....

That surface has to be CLEAN! make sure it's clean and with no corrosion on it. Tiniest bit of corrosion will make it impossible to get in properly.

Chris.
 

morebacon

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So I finally got the gimbal in today. Kept it in the freezer for a couple of hours, then it went in smoothly with the right driver.

Now on to replacing the bellows. There's a protrusion on the upper one and a channel on the gimbal housing. Is the protrusion supposed to sit in the channel? Stupid question, I know, just want to make sure this is the case before I glue everything down.
 

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alldodge

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Yes, the protrusion goes inside the groove with bellows adhesive

Also note there is a top and bottom of the bellows
 

morebacon

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Yes, the protrusion goes inside the groove with bellows adhesive

Also note there is a top and bottom of the bellows

Thank you, this was very helpful! I replaced all the bellows and hoses and got everything back together, but that shifter cable boot was a major PITA to tighten on the transom side. I couldn't get any socket in there, not even the flexible one. Then I got a joint socket adapter set that swivels and that was it, a piece of cake!

I also had trouble with the exhaust bellow, as it was not going in completely, then sliding off. Until I figured out what the real issue was - the tip of the water hose clamp was not letting the bellows slide in completely, so I had to bend it back, away from the metal mating surface.
 

alldodge

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The manual list a specific sequence in tightening the clamps, and the exhaust uses a long thin screw driver inserted thru the port side of the transom assembly to tighten it

boot.jpg
 

morebacon

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The manual list a specific sequence in tightening the clamps, and the exhaust uses a long thin screw driver inserted thru the port side of the transom assembly to tighten it


Thanks for that, appreciate it! I did use the same manual for the steps. My issue was on the bell housing side, but all good now!
 
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