1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP!!!!

[Litetwin4]

I have a leaking transom seal on my stringer outdrive and I would like to know if it is worthwhile to fix it. I have received so much contradictory information I don't know what to believe.

Q1) Is the transom seal on an OMC stringer outdrive an inherently bad design which is prone to leakage?

Q2) What is the life expectancy of a properly installed seal?

Q3) Are there any other items which should be replaced due to taking on water when the seal failed?

Q4) How bad is it to replace it myself. (I am mechanical)

Here is what I have been told when I checked into having the job done.

The local marina told me they normally turn these jobs away. However, since the boat is in great shape they would do it for time and material. They would not agree to a set amount however they estimated $950. I don't like open ended quotes and it seems high to me.

Next I called two independent marine repair sources and here is their feedback;

First one told me don't bother to replace the seal on a stringer outdrive. It is a bad design and stated the maximum life expectancy of the new seal is 2-3 yrs. He basically told me to sale the boat as is and take my losses no matter how nice the boat is.

The other was happy to replace it for $750 but would only guarantee it not to leak at the time I pick the boat up.

The boat is an antique however it is in great shape and runs perfect. It would be a shame to see it scrapped out.

Can someone give me some straight talk on this?

 

[GMC2003]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Took me 10 minutes.... but I had the outdrive off at the time. It is easy. $950 is a bit steep. I got my seal for $120 on eBay. I'm pretty sure the seal that was on mine was original when I replaced it (33 years old). So, in my opinion it is easy to do.

That being said, I think you're supposed to run a thin bead of 5200 or 4200 around the edge of the seal, and then put some on the screws. If you don't plan on taking the outdrive off, people have slid the seal over the whole outdrive (prop off) with soap and water, tighten the screws down, let it dry, and get on your way. One last thing, be absolutely sure that the seal is on correct, if you put it on upside down...... well it'll only last a couple years. Hope this helps.

 

[Howard Sterndrive]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Q1) Is the transom seal on an OMC stringer outdrive an inherently bad design which is prone to leakage?

no, but muskrats like to eat the natural rubber - there is a protective cover from OMC, and some use aluminum screening if mooring a boat in the vicinity of hungry "water-squirrels"

Q2) What is the life expectancy of a properly installed seal?

5 to 10 years for the GLM or Sierra brands
probably 20 years from an OEM one

Q3) Are there any other items which should be replaced due to taking on water when the seal failed?

no

Q4) How bad is it to replace it myself. (I am mechanical)

very easy - 1.5 hour DIY job - remove prop trim fin anode and water director covers, use lots of hot soapy
and it can be stretched over the outdrive carefully
sounds like the marinas in your area just don't want easy revenue

 

[NW Redneck]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Howard is right on. It's an easy job. I did mine a few years ago and it only took me about an hour. I took longer to get the old one off and clean off the old sealant than to get the new one on. I did mine without removing the drive. My old one wasn't leaking and looked in OK shape, but I decided to replace it as it was the original from 1976! I kept the old one as a spare as it is still nice and pliable. The boat had been stored inside which I think contributed to it's longevity. UV is the biggest enemy of rubber so if you can keep it out of the sun it will last a long time. As mentioned make sure the new one goes on the right way up or it will fail prematurely.

 

[Litetwin4]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Thanks for all of the great feedback! OK, I have decided I will do it myself and save my little Starcraft.

It obvious how the new rubber bellow seals against the hull however, I am not sure how it seals against the outdrive.

Is it sandwiched between two parts or is it just by the tight fit as a result of stretching it over the outdrive?

 

[GMC2003]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Got a huge hose clamp on the inside, you have to pull the plate off and pull the seal back to see it.

 

[Litetwin4]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

I don't see any plate. What plate are you referring to?

 

[GMC2003]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

I guess ring would be the proper term... There is an (Aluminum?) Ring that fits inside the seal that runs the circumference of the seal. You pull it off, then the hose clamp is tucked inside the boot. Pull it back to where you can get to it and loosen it. Then pull the boot off and put the new one on...

 

[Litetwin4]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

Ok, I can see the ring and the clamp. Thanks

I need some input on which brand of replacement seal I should use. Most of the seals available on Ebay are Sierra brand. However, I have noticed several postings which state the aftermarket seals do not hold up.

Do you know if this is true?

Do I need to purchase an original OMC brand seal?

 

[southkogs]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

While you're in there, if you've filled the bilge with water you may want to check the trim motor and make sure it hasn't gotten corroded. I think that's what got mine a while back.

If yours is working fine, don't worry about it too much.

 

[Litetwin4]

Re: 1985 16.5 Ft Starcraft w OMC 120HP Stringer Outdrive (Leaking Transom Seal) HELP

I just installed a brand new trim motor a month ago.

I was able to detect leakage at the boat launch.

The water level never go up to the trim motor. Thanks for your feedback.


I still need to know if the aftermarket transom seals are poor quality. Do I need to buy an OMC factory seal ?