Spun engine coupler 1984 Merc 470, opinions?

[ErieRon]

Hello everybody...

I have a 1984, 23' Imperial with a Merc. 470 & Alpha drive. Engine S.N. is 670XXXX.

The drive has been stolen twice and replaced both times by a local certified Merc dealer. The S.N. on the current drive is OA706258. The identifying marks on the drive are "Alpha One-Counter Rotation". 1.62R. It has the long coupler shaft (9-1/2") with three o-rings & no pre-load pin. Just background, although I really don't know if it's a One, Gen II, R, MR etc...

I have known that I spun my engine coupler since early summer (thanks Don & Co.) and now have it in my shop to pull the engine and repair it. I have discovered that the stringer that the front mount is sitting on is rotten. All 4 lag screws can be removed by hand, two just pulled straight out. The top surface of the stringer is obviously bowed/sunken to what appears to be about 1/4"-3/8". No doubt responsible for the coupler failure.

I inserted an alignment tool yesterday, and to my surprise it slid right in with no resistance at all. Granted, the internal splines of the engine coupler are laying in my bilge, so I understand that there is more clearance now, but I was still surprised. The alignment was the same at all engine rotation positions.

So, is it safe to assume that the loose lag screws allowed it to bounce around enough to shear the coupler splines?

And, now that I am committed to pulling the engine and repairing the stringer, how much adjustment is there in the front engine mount itself when properly installed? In other words, if I bring the stringer up to it's original height, it will be higher by the 1/4"-3/8" that it is now bowed which will obviously affect the current alignment and require adjustment.

Lastly, to save all of you from what you're certainly dying to tell me, my 470 has been great for 25 years. While it's out, I will be doing all of the preemptive fixes, i.e. Alt. conversion, lower shift cable, front seals etc...and, yes, checking the transom and remaining stringers.

Here's a picture of my stringer, and my coupler splines laying in the bilge area...

http://s977.photobucket.com/albums/ae255/rsl4fbkt/?action=view&current=Stringer.jpg

http://s977.photobucket.com/albums/ae255/rsl4fbkt/?action=view&current=Shavedsplines.jpg

Thanks in advance for any advice/opinions.

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

Man Ron...You have your winter project cut out for you!

I would think that building the stringers back to the original height will still allow plenty of adjustment room.
Hopefully you will get another 25 years out of her after all that work.

Remember to post up some pics during the rebuild in the restoration forum..

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

Thanks Gary,

I do have a big project for sure, but I'm fortunate enough to have a nice heated shop and 4 months of Cleveland winter to do it.

I thought I read somewhere that there was about 1/2" up and down in that front mount adjustment, but can't find it now.

I'll definitely post up some pics as I get into it....

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

I would think it would be at least that much or maybe up to an inch or so.
I never pulled a 470.

Hey,you could just get crazy and drop a small block chevy engine in it...lol!

I know all about those Cleveland winters.I grew up in Toledo and have family in Cleveland. Sure don't miss that weather!
It is 75* here right now...just took the motorcycle for a spin a little while ago.

 

[Bronc Rider]

Re: Spun engine coupler 1984 Merc 470, opinions?

So, is it safe to assume that the loose lag screws allowed it to bounce around enough to shear the coupler splines?

Yes. I'm surprised you could stick the alignment tool all the way in though.

, to save all of you from what you're certainly dying to tell me, my 470 has been great for 25 years. While it's out, I will be doing all of the preemptive fixes, i.e. Alt. conversion, lower shift cable, front seals etc...and, yes, checking the transom and remaining stringers.

So, you're going to replace the drive, coupler, alt conversion, cam seals, and replace stringers (very doubtfull its just one) on top of regular maintenance? Oh yeah, you will also need a new deck unless you're going to try and re-use it. I know you dont want to hear it but I'm gonna say it anyway. SELL IT AND RUN AWAY.
Good luck.

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

I knew that kind of comment was coming soon....

 

[ezmobee]

Re: Spun engine coupler 1984 Merc 470, opinions?

ER is pretty much our sole satisfied 470 guy. He better be keeping it!!!!

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

ER is pretty much our sole satisfied 470 guy. He better be keeping it!!!!

Agree! He has had it for years correct?
I thought i read a post where he has owned it since it was about new..

 

[Bondo]

Re: Spun engine coupler 1984 Merc 470, opinions?

how much adjustment is there in the front engine mount itself when properly installed?

Ayuh,... The adjusting screw is right there above the crankshaft in your 1st picture,...
Measure it's travel...

Personally,... When doing that, I hang(sky-hook) the motor on the alignment bar to determine the Exact height/ location for the motor mounts....

I inserted an alignment tool yesterday, and to my surprise it slid right in with no resistance at all.

Ayuh,... New fresh Splines are What,..?? .100",.. .125" tall,... Xs 2, that's an Extra 1/4" of available space....
No surprise the bar Fits....

So, is it safe to assume that the loose lag screws allowed it to bounce around enough to shear the coupler splines?

Ayuh,... Absolutely....

Lastly, to save all of you from what you're certainly dying to tell me

he, he, I won't say a Word, other than Good Luck my friend.....

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

Gary & Ezmobee; I'm keeping her...no worries there. I did buy it new in 1984. I've been very good to her and she's returned the favor. Economical to run, enough power to get out and kill Walleyes on Lake Erie, and come home cruising around 30 mph watching the sunset...and plenty of other assorted fun

I'm a little jealous about the 75 & sunny/motorcycle stuff Gary ! It was 43 here today, but 70 Saturday...you can't tell me you don't miss that

Bronc Rider...you sound eerily like my ex-wife......is that you Mary ?

Bond-o; Thanks for the input. Great idea hanging the motor to get the location. I'll have to measure the travel on the screw, I wasn't sure if it was all available for adjustment or not. Also, wasn't sure what the I.D. of a new coupler is since mine is in the bilge and I haven't bought the new one yet. That all makes sense and I'm glad to know it before I jump in. Thanks again.

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

Bronc Rider...you sound eerily like my ex-wife......is that you Mary ?

Too funny!!

Ron,
Today was our last day of warm weather....rain and cold heading this way for the rest of the week....
Sometimes i do miss the snow but that is rare...

I DO miss those walleye and perch fried up golden brown...Its been years since i ate that!

 

[Don S]

Re: Spun engine coupler 1984 Merc 470, opinions?

You guys keep referring to the "Stringers" but the 470 doesn't sit on the stringers. Just a glassed over wood block BETWEEN the stringers, not even connected to the stringers in most cases. It's set up like the 3.0L and 165 inline 6 engines with the cross piece.

How did your coupler fail? If the rubber in the coupler failed, that is alignment only, if the splines in the coupler went out, that is lack of lubrication generally. But if it's way out of alignment, they tend to work the grease out of the spines. But it's almost impossible to install a drive when they are that far out of alignment.
Your alignment could also be due to rear mount failure. I won't even replace a coupler on an engine without doing the rear mounts too. They aren't that expensive, and you have to pull the engine out of the boat to do it.

 

[Bronc Rider]

Re: Spun engine coupler 1984 Merc 470, opinions?

Gary & Ezmobee; I'm keeping her...no worries there. I did buy it new in 1984. I've been very good to her and she's returned the favor. Economical to run, enough power to get out and kill Walleyes on Lake Erie, and come home cruising around 30 mph watching the sunset...and plenty of other assorted fun

I'm a little jealous about the 75 & sunny/motorcycle stuff Gary ! It was 43 here today, but 70 Saturday...you can't tell me you don't miss that

Bronc Rider...you sound eerily like my ex-wife......is that you Mary ?

Bond-o; Thanks for the input. Great idea hanging the motor to get the location. I'll have to measure the travel on the screw, I wasn't sure if it was all available for adjustment or not. Also, wasn't sure what the I.D. of a new coupler is since mine is in the bilge and I haven't bought the new one yet. That all makes sense and I'm glad to know it before I jump in. Thanks again.

LOl. My first boat was equipped with a 470. It was not new like yours when I got it. Needless to say, I had many problems with it. Hey, at least I'm not just jumping on the hate 470's bandwagon, I actually got to screw around with one. Regardless, I hope all your plans come together and you get back in the water next season.

EDIT: It sounds like your wife had a good eye on what boats to avoid. Did she make ya sell any Ford Pintos?

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

You guys keep referring to the "Stringers" but the 470 doesn't sit on the stringers. Just a glassed over wood block BETWEEN the stringers, not even connected to the stringers in most cases. It's set up like the 3.0L and 165 inline 6 engines with the cross piece.

How did your coupler fail? If the rubber in the coupler failed, that is alignment only, if the splines in the coupler went out, that is lack of lubrication generally. But if it's way out of alignment, they tend to work the grease out of the spines. But it's almost impossible to install a drive when they are that far out of alignment.
Your alignment could also be due to rear mount failure. I won't even replace a coupler on an engine without doing the rear mounts too. They aren't that expensive, and you have to pull the engine out of the boat to do it.

Thanks for chiming in Don. I called it a stringer for lack of a better term. I understand the difference and realize it's just a chunk of wood glassed in. Mine is not tied into the actual stringers, but possibly the front edge of the engine box.

My coupler splines failed, in that the splines were sheared off lengthwise, rubber is in tact. In the photo in my original post you can see the crests of the splines laying in the bilge...maybe 1-3/4"-2" long strips.

I pulled my drive in July and it came right off...no resistance at all. My alignment tool goes right in today with no resistance either. I will definitely address the rear mounts as suggested, but does it make sense to you that the loose lag screws and bouncing around sheared the splines vs. major, overall misalignment? Doesn't really matter I suppose, just curious.

I don't have a grease zirk on the coupler, nor could I reach it if I did. Good call though on the grease being worked out. You can actually see where it was slung out in the same area as the sheared coupler spline remains. I have to admit, my drive hasn't been off in years because I was stoopid way back then about drives...now I know better Thanks again for the input, I really appreciate it...from everyone.

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

LOl. My first boat was equipped with a 470. It was not new like yours when I got it. Needless to say, I had many problems with it. Hey, at least I'm not just jumping on the hate 470's bandwagon, I actually got to screw around with one. Regardless, I hope all your plans come together and you get back in the water next season.

EDIT: It sounds like your wife had a good eye on what boats to avoid. Did she make ya sell any Ford Pintos?

Bronc, that's funny...no Pintos, but she made me do a lot of shi! that I didn't want to, and got way more than she was worth when the dust settled. Oh well, at least she didn't get my beloved 470...

Thanks for not hating too much...

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

Too funny!!

Ron,
Today was our last day of warm weather....rain and cold heading this way for the rest of the week....
Sometimes i do miss the snow but that is rare...

I DO miss those walleye and perch fried up golden brown...Its been years since i ate that!

Geez Gary, I was all set to have some homemade chili and watch my Browns get their azzes handed to them by Baltimore...now I might have to thaw out some walleye instead and fry a couple up...

 

[Don S]

Re: Spun engine coupler 1984 Merc 470, opinions?

I really don't think the engine will lift up in the front that much. If it did, I would think the lag bolts would be sticking up a bit from being lifted. Even if the engine set back down, I can't see the lags falling back down into the holes and being flush again.

I have to admit, my drive hasn't been off in years

There is why the splines went away.

 

[ErieRon]

Re: Spun engine coupler 1984 Merc 470, opinions?

I really don't think the engine will lift up in the front that much. If it did, I would think the lag bolts would be sticking up a bit from being lifted. Even if the engine set back down, I can't see the lags falling back down into the holes and being flush again.



There is why the splines went away.

Well, I was really hoping you wouldn't catch that part...

'nough said, and I've learned my lesson.

 

[Gary H NC]

Re: Spun engine coupler 1984 Merc 470, opinions?

Geez Gary, I was all set to have some homemade chili and watch my Browns get their azzes handed to them by Baltimore...now I might have to thaw out some walleye instead and fry a couple up...

Yep...rub it in man!...lol! They are some good eating!
The homemade Chili sounds good too...Dang it! Now i'm starving...

The ole lady is working late tonight so no dinner yet..
I do have a big pot of beans and ham cooking for later. I best get to making corn bread!

Ok....back to regular programming...

 

[littlebookworm]

Re: Spun engine coupler 1984 Merc 470, opinions?

I'm not familiar with the 470 engine, but I am with the Pre-Alpha and Alpha I drives. You've said that you've had two drives stolen already. I'd strongly suggest that you get in the habit of pulling your drive at the end of each season and bringing it inside somewhere safe. Two drives stolen aren't cheap. Pulling an Alpha is relatively easy, and since you're contemplating doing the kind of work on the engine etc. that you described, you're obviously capable of pulling the drive. Stick a plastic cover on the open housing and no critters can get in. You can find plans for a stand for the drive elsewhere on this site. If not, let me know, and I'll post pictures of mine. It's not fancy but it holds the drive, makes it mobile on land, and makes it easier to remove and install on the boat. Good luck with your repair. P.S.Your winters are worse than ours here in NY. Hy