Why do plugs blow out?

[Seadeals]

At speed, water is being forced through the intake grate with considerable force. When a plug's locking mechanism fails, the water follows a much easier path up the tube than through the impeller blades, which in the first few moments, propels the plug rapidly out of the tube. It is a very large leak in the pump system.

 

[cane.mba]

It would be interesting to see the year and model of boats that have suffered blow outs. I wonder if it's an age issue, meaning more plug failures occur after they are 3 years old or older. Has anyone gathered any data or know of any statistical analysis done regarding blow outs?

 

[txav8r]

As far as I know Mike, @cane.mba , all ages and models with the push button plug have had at least a representative blowout. It isn't just operator error, the plug comes unlocked.

I am in the camp of "no lube" but I remove/clean/rinse/dry them. I leave the laying over the clean out tube and not down in the hole. Yamaha says use lube on them...it attracts dirt and grime, and that then makes them hard to install at times. It is also very hard to clean the grease off of them, and of course, if it is a petroleum product it causes softening of the ABS material the lower plug half is made of, then it swells. But the unlocking is the main issue here. Lock em up boys, and keep em dry and out of the hole when not in use...even if your wet slipped! And hey, if they swell or the seal stops sealing well, just get a repair kit and fix them. We have answers today, just a few years ago, we had to perform heroics to keep them working, because a whole plug cost around $300!

 

[Jim Robeson]

I have to say the first time my plugs blew liked to scared the mess out of me. But I truly believe it was me not making sure that it was seated correctly. Since then I have installed EZ Locks and have never had a problem since. I do make sure that the plugs are in correctly even with the EZ Locks.

 

[cane.mba]

I rarely took out my plugs the first season, last year I was a little better about it. So far this year I'm making it part of my post outing process. I take them out, and put the on the swim deck after drying them off and removing any gunk they may be stuck to them.

I also coated the lower piece of the plug with Rejex after I used Rejex on the hull, tower, and windshield. So far only one outing but the plugs were amazingly clean after.

 

[txav8r]

Cobra Jeff has another video besides that one that is very good, and a very thorough explanation about them on this thread...
http://www.jetboaters.net/threads/ez-locks-for-people-wanting-to-replace-the-pin-fix.1055/

 

[maboat]

They are behind the impellers so the impeller is pushing water against them.

This is not true. The clean out plugs are in front of the impellers so the impeller is NOT pushing water against them.

Not sure if that was a typo or not, but just wanted to make sure everybody has the correct info

 

[billyb]

Hey, not trying to hijack this thread, but I recently installed my ez locks. They are great, but...is there a trick to getting them connected in the tube?

I had a hell of a time finding the hole (insert joke here). And as I type this, I am wondering why I couldn't put the locks in hole, insert and lock the plug and then make the locks touch.

Thanks!!!

 

[Boat Crazy]

@billyb. I think you figured it out. Insert the locks before placing in hole, insert in hole, Hit the locking lever. If you listen you may be able to hear them click in. To verify they are locked just look to see if the pins are touching each other.

 

[scokill]

I put my ez locks in after and after years I can do it without looking. I'm in the no lube camp. I've had to do the lower half kit and I think that lube shortens the life. If you pull them every time you shouldn't need lube.

First time my plug blew it shot my tow rope and telescoping paddle 30-40' in the air. It broke the strut and one latch, and the cleanout tube came off of the hatch cover. Didn't flood the engine compartment, but there was a lot of water. I think I was 2 years in and haven't had one since.

 

[GTBRMC]

I use a silicone grease. It helps lubricate on insertion/extraction BUT - as others have mentioned - also attracts sand and grit. Don't, don't, don't use a petroleum based lube! When I replace the lower half of my plugs this year or next, I will go to the no-grease method.

I had what I will call a "near miss blowout event" late last summer. The plug was seated and the dogs locked (I use the three hard tugs method to make sure), but at the end of the day, the plug was seriously wedged in with one dog engaged and the other side dog apparently slipped past its mating tab.

My postmortem effort to root cause led me to the conclusion that a build up of hard water minerals in the metal seat ring caused the plug to sit slightly higher than it should, allowing one dog to slide out while both dogs remained in the locked position.

I got lucky in that the plugged wedged instead of launching. It was, however, a REAL BITCH to un-wedge!

I found a brass wire brush cleans that metal seat ring nicely (but wear some heavy gloves, it is a bit of a knuckle-buster!) This will absolutely be a part of my preventive maintenance program going forward.

 

[Geiger41]

Its crazy with the design on these. There could easily be a cap that covers the whole linked to a hinge lock. Hmmmmmm

 

[0627Devildog]

Reviving an old thread here. . . . . . What can I use to clean the metal seats that the plugs sit in. I found some minor build up (looks like Calcium deposits). Can I just get in there with a brillo pad?

Also, how about something like this for lubrication of the rubber gaskets on the plugs?

 

[Big Shasta]

The Tru-Locks have done their job for me for sure. I still use the footballs on top of the plugs just in case though.

I take them out after every outing, 11 years old boat and they go in and come out perfect every time. Careful putting them in the hole sideways, if your life goes like mine does, you'll drop one in the hole upside down sometime....They are nearly impossible to grab when that happens. I had to get a stick and push it up from underneath while someone grabbed it from the top. Ugh, only me...LOL

 

[maboat]

...Careful putting them in the hole sideways, if your life goes like mine does, you'll drop one in the hole upside down sometime....They are nearly impossible to grab when that happens. I had to get a stick and push it up from underneath while someone grabbed it from the top. Ugh, only me...LOL

I've had that happen too. Do you not have the little "safety" cords attached to the plugs? I was able to pull the upside-down plug back up with the cord. It was still much harder than one would think, but I was able to get it out without crawling under the boat.

 

[BigN8]

The reason that blowouts occur is because of physics. True, the plugs are on the low pressure side of the pump in relation to pressure created by intake water and discharge water. But water entering the intake at speed is under VERY HIGH PRESSURE all by itself. And that is pushing on every square inch of the intake side of the pump, including the bottom of the clean out plugs. If you had a plug release at idle, it wouldn't blow out with the same force, but it would then be pushed out of the clean out tube when you tried to accelerate and you wouldn't get any high pressure out the back of the pump to move the boat very fast.

Even a brand new clean out plug can become unlocked and blow out. Putting some form of locks on them is absolutely necessary. If you go to jetboatpilots or Cobrajetsteerings websites, you can find links these guys have done showing the internal workings of the plugs, and how easy it is for a vibration to actually cause the internal lock to let go, which will result in the "locking dogs or tabs" to retract. And Bruce is right, a dirty or swollen plug can and will make it more difficult to get it "seated" correctly, and that can make it very hard to get a good "lock" when your installing them. So keeping them clean and dry, and outside of the tube when not in use is important too.

Mel. Your write up is very good on the forces on the plugs but I dont think after market plug locks are "absolutely" necessary. Good diligence installing them will get the job done in my 5 years of experience.

 

[Bruce]

Can I just get in there with a brillo pad?

Mine came with heavy buildup. I used a pressure washer, Brillo pads and a wire brush.

You should not need lube.

 

[tdonoughue]

That is the type of lube I use. I get mine from the pool store. It goes on all of the gaskets for the pumps, etc. on the pool, too. I can't really attest that it is 'needed', but I have used it and had no issues. To my mind it is cheap insurance.

 

[Big Shasta]

I've had that happen too. Do you not have the little "safety" cords attached to the plugs? I was able to pull the upside-down plug back up with the cord. It was still much harder than one would think, but I was able to get it out without crawling under the boat.

You're right, they would have saved me...but no, I didn't have them connected.

 

[MOA_Chaser]

My boat is 11 years old, I don't lube the plugs, I have no reason to believe that they were lubed before me, and I have zero issues with the plugs. Using Cobra EZ Locks here. I see no reason to use lube on plugs. If you NEED lube, they're probably defective anyways and should be rebuilt IMO.