Decision to make regarding stripped stator oil plug

[jasguild]

I took my boat to a mercury dealer here in Tampa with the hopes that they could change the oil in my stator.

They said that they cant get the plug to move and are concerned it would strip the stator thread if they apply too much pressure which would require a new stator.

They said my first option is to leave it as is and not to change the stator oil. They think that this oil needs to be checked regularly but not necessarily changed regularly. The risk with this option is that if the stator oil is low or with poor viscosity, the stator may ultimately fail. This option according to them would not put the stator at risk immediately (if the oil level is high and with good viscosity)

The second option is to have them apply more pressure to get out the plugs. If the allen heads strip they can then resort to an easy off tool to remove the plugs. The risk here according to them is that the stator thread may get stripped and they dont believe there is enough metal in the back of the stator to do a rethread. As such I would need a new stator. The second risk according to them is that the easy off tool can break and if it does, it often cannot be removed which would mean I would need a new stator.

I have no idea what to do.

Please help

Coastiejoe edited the titl for spelling reasons.

 

[Coastiejoe]

I would use TORX bits. Use a hammer and drive one into the Hex head area. This will let you bite into new metal. Use an impact hammer as well. I am not where I can post a picture right now, but I will do so as soon as I can so you know what I am referring to...

 

[Coastiejoe]

Here are the pics. A HAND impact driver, NOT and air impact gun.

 

[jasguild]

Thanks for the suggestion. I will mention it to the technician.

Is there a real risk of my stator being destroyed by attempting to remove this plug?

should I take it somewhere other than the mercury technician? He says they have removed other tough screws before but never from a stator.

 

[Tim75]

You don't say which plug is stuck. Is it the center plug or the upper plug? If it is the center plug, the whole stator can be removed and the oil drained (Warning- Big mess!) Re-assemble, then SLOWLY pump in new oil into the upper hole normally. New plug with teflon tape.

Can you tell what is holding the old plug? Is it corrosion or sealer/loctite? Heat from a heat gun (NOT torch) may help. Be careful banging on this casting. If you can get the stator off, a competent machine shop can remove the plug.

 

[jasguild]

Tim

They indicated that both plugs are stuck. there is no signs of corrosion so i would guess that it is caused by sealer/locktite.

thanks

 

[Waterluvr]

Use a Hanson EX4 spiral flute extractor to get those out, nothing else will touch those. A cheap extractor won't work and you do not want to have at it with a torx bit it won't budge and you'll tear up the center of the plug bore and remove your first option of using the EX4.

There's enough metal in the plug to widen the bore and go up to the next size extractor (EX5) if it's already punched out, use a 19/64 bit and just get it started into the plug about 3/8" at most until the front of the extractor gets a solid bite, works every time.

 

[jasguild]

Worse case scenario, would I be able to drill new a new hole and retap new threads in the stator if I cant get this thing out?

The mercury tech kept mentioning an easy out tool and warning me that it might break (isnt the plug made of brass? if so this is not the hardest metal out there.) But if a regular easy out is not the best option maybe I should get back the boat and do this on my own. Agreed?

Finally WaterLuvr, were you able to do this with the stator in tact?

Thanks again

 

[Waterluvr]

Worse case scenario, would I be able to drill new a new hole and retap new threads in the stator if I cant get this thing out?

The mercury tech kept mentioning an easy out tool and warning me that it might break (isnt the plug made of brass? if so this is not the hardest metal out there.) But if a regular easy out is not the best option maybe I should get back the boat and do this on my own. Agreed?

Finally WaterLuvr, were you able to do this with the stator in tact?

Thanks again

Your situation is not unique by any means, few people ever pay to have the regular maintenance done on them and everyone I get in that isn't owned by a regular customer is like that from having been in there for years. I don't even try to take them out with a ball end wrench unless I have been into that stator to service it during the last season the service pack includes both new brass plugs in the same package.

Any tech with experience working on these will tell you upfront those plugs are a known issue and should include new ones in the service parts quote unless they have been off already that season for some reason, you never should have been put into worry mode like this they come right out of there if you know what you're doing and use the right tool the first time around I wouldn't have said a word about it to you otherwise and simply removed them and performed the service for you it's the shops responsibility and obligation to a customer to know what they are doing and have the tools and ability to perform the service.

Before you resort to taking a drill to the plug and trying to retap anything, find a local tool and die guy that can take those out of there for you if the marine service offerings in your area can't help you. A good sharp spiral flute tool steel extractor will back those right out of there no problem in the hands of someone that knows how to use it.

You will create a problem for future service of that stator to a subsequent owner if the original plugs are no longer able to to be used.

 

[jasguild]

Got it. My first option is not to retap. I was just trying to assess my worse case scenario.

Out of curiosity, you mention you dont even bother to try to use a ball end wrench, does that mean you go straight to using the spiral extractor?

Thanks again for all your comments. I will keep you posted

Thank you

 

[Waterluvr]

Correct, you're getting charged for a new vent screw and plug in this scenario no matter what and you'll never get a better bite on the plug than right here and now with the metal that remains in it any rounding of the plug bore from the ball end wrench will diminish the initial bite of the extractor.

While Joe meant well recommending the use of a torx bit to try and get it out that's a perfect example of what not to do, you want the center of the bore to remain as concentric as possible so the extractor exerts force in a uniform manner around the circumference of the plug threads. You get to far off to one side from metal damage and you'll just bind the plug in the hole it's in when turning force is applied to the extractor.

A good spiral flute extractor grabs the bore it's inserted into immediately and does not let go, when force is applied is buries itself deeper into the bore and takes a harder bite as it turns to the left.

 

[jasguild]

Just got off the phone with the tech and informed him of the suggestion to use a good spiral extractor. He assured me they remove lots of frozen bolts and that he believes it will move however he wanted me to be aware of the "risk" and cost of a new stator. (GULP) I gave him the go ahead and will keep my fingers crossed.

One more question, what sealing product do you typically use when installing the new plug? I have a feeling the previous owner used a thread locker. Going forward I will be doing this maintenance on my own and want to make sure i am using the right product.

Thanks again.

 

[Waterluvr]

That requires an anaerobic sealant, either 518 Loctite or Permatex is what you seek. Some auto parts retailers offer that in reduced size tubes or one time use foil packs to save you some money you'll only need a little bit each season and it's pricey to waste a tube of it.

I wouldn't use last years sealant for that application.

 

[jasguild]

I take your last statement to mean once the sealant is opened, it wont last a year, correct?

I searched for 518 anaerobic sealant and all I am finding are gasket and flange sealants. Is that what I am looking for?

Sincerely

 

[Waterluvr]

I take your last statement to mean once the sealant is opened, it wont last a year, correct?

I searched for 518 anaerobic sealant and all I am finding are gasket and flange sealants. Is that what I am looking for?

Sincerely

Yes sir, that was originally developed for flange applications. It has a great track record sealing oil plugs in place without leaking or taking a set around the threads and cementing it in place. Anaerobic sealant cures in place without the presence of oxygen, and this formulation has both a desired gap filling ability plus resistance to petro chemicals.

Now I can't say one way or another regarding the shelf life, all these products have data and tech sheets available from the manufacturer but I can't use a tube of something in good faith that I know has been open for any length of time. Exposure to hot and cold, moisture etc why take a chance on something sealing a submerged plug thread?

Here's the smaller tube I was referencing, it's only 2/10 of an ounce there's plenty to coat the threads on several jobs during the season I'll use several of these but it's always fresh that way. I use it on all gear case oil plugs that do not have a backing gasket such as a Mercury or Yamaha outboard gear case or pressure vent plug would have.

 

[jasguild]

Thank you. Still waiting to hear back from Lands End Marina on how the surgery went

 

[jasguild]

They were successful in getting out the top plug. They then sucked the oil out and refilled the stator from the top one. However according to them they didnt want to "push their luck" with the middle plug which was also stuck.

At least I got one out and my oil changed. I have a year to ponder whether I want to tackle the middle one or just repeat what they have done with the top one.



Thanks everyone

 

[Coastiejoe]

If it is stuck, in bad condition, and doesn't leak, I think I would leave it. As long as you have good access to the top plug, you have a means to do the required maintenance.

 

[jasguild]

knowing me, I will be tempted to attempt to remove that stuck plug everytime I change the stator oil. I am just the type of person who always wants things to work the way they should work. That's a flaw in my design I guess.