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View Full Version : Transom 22, good news..1996 502Mag 22.



Pismo
09-17-2014, 08:53 AM
So my gimbal is shot, as is the steering pin, seals around it, etc so instead of replacing just the ring and pin i decided to change the entire transom assembly. In addition to a new gimbal ring, pin, etc, this also replaces all my other original items such as gimbal bearing, ujoint and exhaust belows, rams, etc and I can sell the old assem. This would also give me a chance to closely examine the transom for rot. After reading many transom threads I was very fearful that mine was shot or on its way. To my very happy surprise the transom is solid still, very solid. No issues anywhere i could find.


A few things i noticed.
--The transom is exactly 2" thick with 1/2" of glass/gel on the aft edge and then plywood with layers of glass going forward.
--The transom was not a mosaic of dozens or 4 or 5" square pieces of plywood (like I read it would be somewhere) it is solid.
--A nice 3-4" semicircle was cut around the drain plug to help keep water from soaking in there, very nice.
--Everything looked sealed up nicely and solid still.
--There are large 2" holes thru the stringers for water to pass thru.
--The stringers are huge, probably 2" thick.
--Removing the engine took 2hrs and another hour to remove TAssem. 10m to remove drive and engine hatch (which needs to be unscrewed from deck) So 3-4hrs total. Not bad.
-- Lots of wires outside the Merc 9pin standard plug. Mercathode, trim limit, trim sender, others that i dont know what they are, etc.
--Donzi builds a good solid boat.
--Cleaning took the longest.
--Tighten those two top gimbal ring nuts every fall as part of your yearly maintenance. I waited until it was loose and this bought me couple more years but it was still too late.
--If anyone is worried about their y pipe leaking where it hooks to the transom assembly, look elsewhere first, mine was very tight with a gasket and lock washers on all 4 bolts. These were the hardest bolts to remove, very tight.

Let it dry out good over the winter and then paint bilge and re assemble in spring.

Overall a fairly easy job with few surprises. Spring may be tougher getting it back together.

Some photos, starting, hatch/drive, engine out, dirty with TA, dirty TA out, clean, clean.

Cheers

Mr X
09-17-2014, 09:17 AM
Great idea, replaces all the worn stuff in one shot...and is much more cost effective.
Nicely done!

Pismo
09-17-2014, 10:09 AM
Great idea, replaces all the worn stuff in one shot...and is much more cost effective.
Nicely done!

Cost was certainly a factor but getting a good look at the transom was important.

The 631 magnum TranAssem cost $1900.
Parts to do it the other way were about $1600.
Either way was a lot of labor.

To get PerfMar to do it was $2300+ unknowns.

If I sell the old TA for a few hundred i should be about even and everything is new rather than "fixed" and I was forced to remove motor and get a look at the transom.

CHACHI
09-17-2014, 12:05 PM
Will you be replacing the coupler?

Ken

Morgan's Cloud
09-17-2014, 01:09 PM
Will you be replacing the coupler?

Ken

I think that's a very good idea. A little extra coin ? Yes , but it'll be done once and for all .

Also , just my humble opinion , don't let anyone talk you into the 'transom seal is all you need' viewpoint.
Put a nice bead of polysulfide based sealant under the new trans plate first to work in conjunction with the seal.

Also easy to disassemble later on if ever needed . 5200 = the other invention of the devil .

Pismo
09-17-2014, 04:14 PM
I think that's a very good idea. A little extra coin ? Yes , but it'll be done once and for all .

Also , just my humble opinion , don't let anyone talk you into the 'transom seal is all you need' viewpoint.
Put a nice bead of polysulfide based sealant under the new trans plate first to work in conjunction with the seal.

Also easy to disassemble later on if ever needed . 5200 = the other invention of the devil .

Where would you put it? Just inside or outside of the factory seal gasket?

Morgan's Cloud
09-17-2014, 05:27 PM
Where would you put it? Just inside or outside of the factory seal gasket?

I like to do the whole area under the trans plate .No missed spots.
Any excess can be left to cure and then trimmed off neatly like an over sized o ring.
Unless of course you like to wipe and wipe .. either way it's worth it.

I can't remember the 3M product I used , I think it was 1001 sealer but the 'Boatlife' Lifecaulk polysulfide sealant is the same stuff should you end up doing it.

Tidbart
09-17-2014, 07:38 PM
Boy, that job looks familiar. :)
Do as much work as you can with the engine out. It is easy now.

Bob

Pismo
09-18-2014, 01:42 PM
Belts, plugs, trim unit solenoids, maybe coupler ($700!) after a good look, just did oil and raw water pump. Any other suggestions? I should remove the VST but up north i never have had any vapor lock trouble. Clean, paint, remount depth sensor more aft. 350 hours fresh water only.

Pismo
09-18-2014, 03:19 PM
There was a tan wire taped to the outside of the 9 pin cable that ran up under the throttle body and then out of sight. It did not go thru the 9 pin. I cut it, it was the only one I could not disconnect correctly.

Anyone know what that wire is?

Thanks

Tidbart
09-18-2014, 03:27 PM
If you decide to do the coupler, there is a company in Quincy FL called Speed and Custom Marine. He sells couplers made by Lord. They make them for Merc. He has good prices on them, worth a look.

Here is a little write up on the coupler replacement via the Merc bulletin that I did years ago. http://www.donzi.net/forums/showthread.php?65476-Coupler-install-per-Merc-bulletin&highlight=

I replaced a lot more part than you will ever have to as my boat was used in salt and neglected.

Bob

Tidbart
09-18-2014, 03:34 PM
Coupler shouldn't be more than $300, if I remember correctly.

B

Tidbart
09-18-2014, 03:49 PM
There was a tan wire taped to the outside of the 9 pin cable that ran up under the throttle body and then out of sight. It did not go thru the 9 pin. I cut it, it was the only one I could not disconnect correctly.

Anyone know what that wire is?

Thanks

That may be the IAT, Intake Air Temperature, sensor wiring. If I remember correctly, the sensor is threaded into the underside of the plenum. It has 2 wires coming out of it, a tan and a black (gnd). That would be an all tan wire with no stripes. The tan wire would go from the sensor to J1 end of the ECM.

If that is not the correct wire, the only other one I see is one that goes from a harness connector for the charging/starting harness to the J2 end of the ECM.

I guess, either way, you have find out where the wires runs.

B

Tidbart
09-18-2014, 04:02 PM
Sent you a couple of PMs.

B

yeller
09-19-2014, 08:29 PM
There was a tan wire taped to the outside of the 9 pin cable that ran up under the throttle body and then out of sight. It did not go thru the 9 pin. I cut it, it was the only one I could not disconnect correctly.

Anyone know what that wire is?

ThanksTidbart is correct on the 2 tan wires. Your water temp gauge also uses a tan wire, but that should be pin #3 on your 9pin plug. If you PM me your email, I will email you the 93~97 Merc 454/502 service manual.

Pismo
09-20-2014, 02:12 PM
Tidbart is correct on the 2 tan wires. Your water temp gauge also uses a tan wire, but that should be pin #3 on your 9pin plug. If you PM me your email, I will email you the 93~97 Merc 454/502 service manual.

Thanks, Tid already sent it. Very nice.

Pismo
05-07-2015, 03:12 PM
Well, started reassembly and found the gasket with the new TA was shot. Packaged poorly and crushed in many places so had to replace that. Bellows adhesive(terrible stuff, stringy, smelly, but works) to hold it down. Then reassem went well. Painted bilge (bilge coat is great), TA on, motor back in, aligned to perfection, then drive slid on easily. Everything works, even the speedo. Steers much better now with a tight gimbal ring. Torqued the u bolt and will do so ever fall.

Pismo
05-07-2015, 03:14 PM
Cleaned and back in service. Toughest part was aligning all those silent choice rubber exhaust fittings, took some time.

New TA had all quick connects for everything so I had to fix those. Adapters came with new TA so easy.

Had a good spin up to Paradise bay, all good, no leaks, slow first trip but all good.

So to conclude, my gimbal ring and pin was very shot, leaking, so I decided to change the TA with a new one rather than just replace the parts. Cost was about the same after I sell the old TA and everything is new. Original drive and motor doing well.

Fairly easy job both removal and install. Still took time tho. Easier than expected. Getting motor back in was toughest part.

Moral - tighten those U bolts nuts every fall as part of normal annual service. Mine got loose and before i noticed, ring was shot.

yeller
05-08-2015, 02:27 PM
So to conclude, my gimbal ring and pin was very shot, leaking...

Moral - tighten those U bolts nuts every fall as part of normal annual service. Mine got loose and before i noticed, ring was shot.

Glad you got it all fixed.

Do you know exactly where your leak was? Bellow, TA gasket, ?
I've got a leak in mine that I just can't find. It's driving me nuts.
What U bolt nuts are you referring too? Are you actually talking about nut 19 and 21?

Looks like you made the right choice in going all new.

Carl C
05-08-2015, 03:45 PM
Looks very nice. Glad the steering police have gone away. :lookaroun:

gcarter
05-08-2015, 04:47 PM
I would guess you're talking about #24. One thing to remember, the torque setting for these nuts is 35'#.
Over time, that U-bolt will stretch and the nuts loosen. It's tempting to over-tighten the nuts. But if the torque settings aren't maintained,
and overtightened, the U-bolt will probably break, and probably in the root diameter of the thread (and just inboard of one of the nuts), where the bolt is the weakest.

I guess I'm talking to everyone w/a Bravo or Alpha. Another thing that's useful if you're rebuilding the gimbal yourself. I bought SST pivot pins instead of steel Merc pins. The stock pins will eventually corrode and leak water through the upper seal. Another useful modification that can be made to your new SST pin is to have a machine shop drill down through the top of the pin and cross drill the pin in the area of the seal and bushing (see picture). combined with drilling and tapping the gimbal
housing and install a grease fitting. This allows periodic greasing of these parts and extend their useful lives.

http://www.donzi.net/forums/attachment.php?attachmentid=82099&d=1258214372

http://www.donzi.net/forums/attachment.php?attachmentid=82100&d=1275358249

yeller
05-08-2015, 05:47 PM
I would guess you're talking about #22.
Thanks George. I'm such an idiot! I kept looking and looking for a "U-bolt" and my brain wouldn't let me see it. :bonk:

gcarter
05-08-2015, 05:56 PM
Thanks George. I'm such an idiot! I kept looking and looking for a "U-bolt" and my brain wouldn't let me see it. :bonk:

And I guess I could have used the correct reference number "24" instead of the incorrect number "22".

yeller
05-08-2015, 06:29 PM
Moral - tighten those U bolts nuts every fall as part of normal annual service. Mine got loose and before i noticed, ring was shot.FYI: I was looking for something else, but came across an article at sterndrives.com that said to never retorque the bolts. Of course, I'm still going to check that the nuts haven't backed off, but I'll be careful to make sure they are not loose due to wear.

"These bolts where torqued to 50-55 ft pounds when the unit was first assembled. It helped the gimbal ring clamp-down tightly on the upper steering shaft.
The ONLY time these bolts should ever be torqued is when the gimbal ring is new and it is being installed for the first time.
They should never be torqued in an attempt to eliminate free-play in the steering. Free-play is a result of wear and distortion in the gimbal ring.
If you have free-play, the gimbal ring has to be replaced. NEVER tighten the two retainer bolts if you have free-play. If you attempt to tighten these bolts there is a good chance the gimbal ring will snap and fail. This usually happens while you are on plane and going fast.

Damage, Injury or Death can result from gimbal ring failure."
I believe they were using an Alpha ring as an example which uses 2 standard bolts instead of a U-bolt...in case you are wondering why they said the "bolts" were torqued (and not "nuts"). Will also explain the different torque amount, as compared George's comment of 35lbs.

gcarter
05-08-2015, 07:11 PM
FYI: I was looking for something else, but came across an article at sterndrives.com that said to never retorque the bolts. Of course, I'm still going to check that the nuts haven't backed off, but I'll be careful to make sure they are not loose due to wear.

"These bolts where torqued to 50-55 ft pounds when the unit was first assembled. It helped the gimbal ring clamp-down tightly on the upper steering shaft.
The ONLY time these bolts should ever be torqued is when the gimbal ring is new and it is being installed for the first time.
They should never be torqued in an attempt to eliminate free-play in the steering. Free-play is a result of wear and distortion in the gimbal ring.
If you have free-play, the gimbal ring has to be replaced. NEVER tighten the two retainer bolts if you have free-play. If you attempt to tighten these bolts there is a good chance the gimbal ring will snap and fail. This usually happens while you are on plane and going fast.

Damage, Injury or Death can result from gimbal ring failure."
I believe they were using an Alpha ring as an example which uses 2 standard bolts instead of a U-bolt...in case you are wondering why they said the "bolts" were torqued (and not "nuts"). Will also explain the different torque amount, as compared George's comment of 35lbs.

Good point Glen. The U-bolt has completely different characteristics than individual bolts.
On the U-bolt, I've seen torque specs stating 55'#, but that's probably just too much. I remember reading an article recommending the 35'# number as a safety factor. As you point out, it's dangerous for one of these things to break.
I won't make a definitive comment about re-torquing the U-bolt. It's very hard to change the bolt w/the gimbal assembled, and the thing needs to be kept tight.
As a side note, if a person does decide to convert to external steering, it automatically removes the threat as there are no forces at all on the tiller. The pin sees no torque, but only thrust which would probably never wear out a gimbal ring.
.

Pismo
05-08-2015, 07:49 PM
Yes ubolt nuts #24. The new TA had them torqued at 55lbs from the factory which according to my manual #16 is correct. I will keep them at that torque as they seem to loosen naturally. New pin looks nice.

Pat McPherson
05-11-2015, 11:10 AM
Retorquing once is probably ok but I would not do it more than that. The threads yield and take a set when the bolt is preloaded. You will fail the threads or yield the bolt if you continue to tighten.

gcarter
05-11-2015, 11:55 AM
I remember torquing the nuts pictured above on my gimbal.
Once I reached 35'#, I could literally feel the bolt stretch, so I stopped. Honestly, it concerned me.