Should we antifoul paint our 1998 SX outdrives?

[Monterey296Twin5.0Gi]

We are hauled out now and having the shipyard paint the bottom of the boat. Several people suggested we paint the outdrives for an extra charge. We pay for regular bottom cleaning and the boat was just cleaned before hault out. Boat sits in a salt water slip year round, with sun and tide flow, so we get a lot of growth on the outdrives.

Would painting the drives help prevent the growth in the crevices you see in these pictures, and would it help prevent growth inside the intake holes for the raw water intake on either side of the drive?

Is it worth the added cost, which is another 50% to the cost of painting the bottom?

 

[Horigan]

Yes, you should paint the drives. It will prevent the growth in the crevices and at the opening of the cooling inlets, but not deep inside the inlets. You should clean the inlet growth out as best as you can, then back flush from the raw water pumps so you don't introduce the broken up crud into your cooling system. The internal passages should stay clean if the boat is used often.

 

[Monterey296Twin5.0Gi]

Yes, you should paint the drives. It will prevent the growth in the crevices and at the opening of the cooling inlets, but not deep inside the inlets. You should clean the inlet growth out as best as you can, then back flush from the raw water pumps so you don't introduce the broken up crud into your cooling system. The internal passages should stay clean if the boat is used often.

Thank you, I was curious since the drives look pretty good if we would just be wasting money and/or just making our bottom cleaner's life easier. I don't think the previous owner ever painted them over 20+ years in salt water, and just had good maintenance on cleaning and zincs.

I just found these bellows sleeves, do you think they are a good idea, cheap at $40 ea.

Home

www.barnaclebusters.co.nz

 

[Lou C]

If you need to bottom paint your boat you absolutely need to paint your drives. I brush on 2 coats of Trilux out of the can and use the spray for where the brush can’t reach. I will usually get through the season with just a few barnacles and slime….
BTW the water intakes have crud in them you want to blast that out. I had barnacles growing in the water intakes and wound up removing the plastic screen inside. I did that in 2013 and it’s run consistently cooler ever since.

 

[Monterey296Twin5.0Gi]

If you need to bottom paint your boat you absolutely need to paint your drives. I brush on 2 coats of Trilux out of the can and use the spray for where the brush can’t reach. I will usually get through the season with just a few barnacles and slime….
BTW the water intakes have crud in them you want to blast that out. I had barnacles growing in the water intakes and wound up removing the plastic screen inside. I did that in 2013 and it’s run consistently cooler ever since.

Thank LouC! I also PM'd you on Hull Truth as I knew you'd have something to add. Do you think I should try the BarnacleBusters bellows sleeves too?

 

[Lou C]

Thank LouC! I also PM'd you on Hull Truth as I knew you'd have something to add. Do you think I should try the BarnacleBusters bellows sleeves too?

Well I usually paint the bellows too; I’ve seen those but never tried them..

 

[cptbill]

I keep my VP duo props painted, just sayin' can't hurt

 

[Monterey296Twin5.0Gi]

Well the outdrives are apart now, and while they were fully serviced with new bearings back in 12-2018, it appears to have failed early. There was water in both bellows, and one gimbal (port) bearing was seized to that shaft, and the driveshaft had turned blue from the heat. The bellows seem to still be intact, but they haven't pulled them out to see for sure yet. Where the water seems to have gotten inside is the previous mechanic didn't use this gasket or any sealant between the two halves of the outdrive!!!!

Is that gasket critical? It seems odd they missed it since the old 2018 invoice from the repair seems to include a lot of VP quality parts and appeared to be a good mechanic.

 

[Lou C]

What you are up against is the difficulty of maintaining stern drives in salt water. The boat yard should be pulling the drives once a season to check the bellows for water intrusion and greasing the gimble bearings and ujoints as well as checking both for roughness and wear. For your next boat since you’re in salt water full time strongly consider outboards instead of stern drives.
The confusion about that gasket has a history lesson behind it. OMC had the Cobra drives introduced in 1986 they had some early problems but those were worked through. However due to bad management and the Ficht outboard fiasco they got into financial difficulties. Volvo was looking to change their stern drive design to match the transom cutout used by Mercruiser. So they went into a joint venture with OMC, redesigning the Cobra to use cone clutch shifting and both the new Cobra & Volvo SX (identical) were sold by each company individually the only differences were that the Volvo was painted silver and had Volvo model #s, and OMCs were painted Charcoal and had OMC model numbers. Even part #s were the same. This went from 1994-1998 after which Volvo bought out the remaining share of the OMC stern drive division. So when the original Cobra was designed that gasket was needed because of how the shift linkage was designed. When they redesigned it, the Volvo style shift linkage no longer required the gasket. So the driveshaft bellows, & gimble bearing are the same between the 2 models; the exhaust bellows are slightly different but are interchangeable. I would advise using ONLY OE Volvo parts for this repair they are now selling a more durable bellows design. That kit you posted a pic of is likely an aftermarket kit that could be used on either an OMC or Volvo. I always advise OE parts for bellows and impellers.
I think your stern drives need at least yearly maintenance including painting with anti fouling and cleaning water intakes.
Also….have your exhaust systems been inspected? In salt water they are good for 5-7 seasons. If you wait too long it will damage & potentially ruin the engines so make sure that gets done.

 

[Lou C]

Also, the bellows has a ridge that has to fit into a groove in the gimble housing mount for it to seal and the screw for the clamp has to be properly oriented so it doesn’t cut into the rubber when you turn all the way to one side. The bellows is assymetic meaning that it has more folds on one side. The side with more folds faces down to reduce cracking from tilting it up. When an OE part is used and properly installed they last about 10 years. If you find that barnacles tore the bellows the new style bellows with the hard plastic mid section should work better for you.
Next boat do yourself a favor no more stern drives UNLESS you have a excellent mechanic to maintain them OR do it all yourself like I do.

 

[Lou C]

PS
there is no way that normal aluminum antifouling will last a year in full time salt water storage, at least not in my experience, I get through season but here that's only 6 months at most. So if you want to keep this boat figure on 2 haul outs per year, one to do all the maintenance after pulling the drives, the other to clean the drives and repaint if needed, as well as checking anodes, gear oil etc.
and as I said....do NOT neglect that exhaust system, if you see rust trails coming from the joint between the exhaust manifold and the exhaust elbow you need to get on that NOW. The exhaust parts can be replaced with aftermarket parts from Barr Marine. There are cheaper options but quality is not always good. That joint is a trouble spot on all wet joint exhaust systems and you just have to keep an eye on it. If neglected you get water in cyls, sticking valves and eventual engine failure.
Here's a few pix, first is removing the drive, for yearly service, second is what it looks like after a season in the salt, third shows the new exhaust manifold (same Volvo style you will have) mating surface, last one shows the installation of the elbow on top of the manifold. I'm not a professional mechanic by any means but I could easily teach myself to do this stuff, its just not that hard, just messy and dirty and you have to bend yourself into tight spaces.

 

[bruceb58]

Well the outdrives are apart now, and while they were fully serviced with new bearings back in 12-2018, it appears to have failed early. There was water in both bellows, and one gimbal (port) bearing was seized to that shaft, and the driveshaft had turned blue from the heat. The bellows seem to still be intact, but they haven't pulled them out to see for sure yet. Where the water seems to have gotten inside is the previous mechanic didn't use this gasket or any sealant between the two halves of the outdrive!!!!

Is that gasket critical? It seems odd they missed it since the old 2018 invoice from the repair seems to include a lot of VP quality parts and appeared to be a good mechanic.

View attachment 350209

A volvo doesn't use that gasket. That looks like an OMC kit.

You should be purchasing an OEM u-joint bellow. They changed the design a few years back.

 

[Monterey296Twin5.0Gi]

Also, the bellows has a ridge that has to fit into a groove in the gimble housing mount for it to seal and the screw for the clamp has to be properly oriented so it doesn’t cut into the rubber when you turn all the way to one side. The bellows is assymetic meaning that it has more folds on one side. The side with more folds faces down to reduce cracking from tilting it up. When an OE part is used and properly installed they last about 10 years. If you find that barnacles tore the bellows the new style bellows with the hard plastic mid section should work better for you.
Next boat do yourself a favor no more stern drives UNLESS you have a excellent mechanic to maintain them OR do it all yourself like I do.

Thank you LouC for the very detail explanation. We feel confident that we have a good mechanic, but I know any mechanic could say the last mechanic did something incorrectly. The bellows and gimbals on both outdrives were done in Dec 2018 with all VP parts according to invoice. So I don't know for sure YET, but I don't think the bellow failed, I think the water got in between the 'gimbal housing' and 'upper unit' where that gasket could go and the went though the grooves on the drive shaft housing flange into the bellows.

Here are my photos and videos, excuse my rambling on the video I was just speculating before the mechanic arrived.

26 new photos · Monday, Sep 20, 2021 📸

Tap to view!

photos.app.goo.gl

Notice how blue the driveshaft got from the heat, the gimbal bearing seized onto it.

 

[Lou C]

When the bellows are installed it is best if the pivot housing is removed because then you can tell if the end that goes on the gimble housing is seated properly. Some mechanics take a short cut by removing the exhaust bellows first and leave the pivot housing intact; and install the driveshaft bellows from underneath. It can be done that way but you can’t see and feel if it’s seated right. Also when they take off the old bellows make sure they clean up any corrosion that might prevent them from sealing. I have also heard it is possible for them to leak from the grease tubes, these can be resealed with Permatex or Evinrude gasket sealer but I never had that problem.