Motor issues - seeking suggestions

[WaskaCrank12]

Hello - I have damage to lower unit of my motor, so if I am to use the motor I will need to replace the lower unit. I am looking into several solutions and seeking to find out if people here have experiences (positive or negative) in solving an issue like this.

1. Has anyone purchased a used lower unit ? if so did it have a positive outcome or negative outcome for you ? (I am researching to make sure what used lower units would be compatible with the motor - which is a 93' Evinrude 90hp V4)

2. Has anyone purchased a re-manufactured lower unit ? positive or negative experience with it ?

3. Has anyone purchased an aftermarket new lower unit ? positive or negative experience with it ?

4. I have an opportunity to purchase a 78' Johnson Javelin 85hp (to potentially replace the 

93' Evinrude 90hp V4), so this might be an option, it is a well cared for engine that runs smoothly, yet it is 46 years old and would require lifting off the engine/cables/ect......

Thank you in advance for your time/efforts/thoughts.

[WRB]

PM member Way2Slow, Kieth is an expert on Evinrude OB’s.

My initial thought is a ‘93 Evinrude is over 30 years now and parts maybe difficult to find in good condition  

Did you damage the lower unit from the power head to the prop shaft or just the gear case and unit under the cavitation plate?

Tom 

[Way2slow]

I would not even consider the 78 motor.  I think it even has a different bolt pattern to mount it.  

Also, that 85 hp is rated off the flywheel so it's really only a 60 - 70 hp using the current rating standards.

 I would check locally for a used LU.  

The problem I have is I have been out of this for a while and don't have a lot of experience with V-4 cross flows but I think they have the small and a different gear ratio so you might be stuck with find one of those.  V-6 loopers I have several good LU's but never did much with the cross flows.

Finding one locally makes life simpler if you happen to get a bad one.  As for buying a used one, I would have no problem provided it's a fresh water unit.  Don't even consider one that was used in salt water.  They are easy to recognize by the corrosion.

[WaskaCrank12]

Hello @WRB

and @Way2slow 

 

Thank you for the replies -- the short story (which is going to turn in to a long story) of the damage to the lower unit is --- the engine was surging a bit last fall so this spring when I de-winterized it I chose to take off and clean the carbs (new kits) and thought it would be wise to also change the impeller/water pump while things were a part (also new plugs/fuel filter/fuel line).......everything was going well (I only have medium at best mechanical skill, so this was pushing my ability limits)....three of the 4 bolts for the water pump housing came off with no problem (I took them off by hand with a socket wrench) - the 4th one broke off, ugh, about halfway into the housing/insert area........a well meaning friend (he has done a lot of work on his motorcycles/4 wheeler engines) said he would give it a try to drill/tap the piece of bolt out - yet it was difficult due to the nature of aluminum - he got part of the piece out and put a "coil" piece in -- and I am thankful for his efforts -- yet I cannot get the metal water pump plate to line up correctly (because the bolt does not go into the insertion area correctly) so that it can be placed/tightened correctly -- my friend was nervous to drill more and I have no skill in this area -- I brought it to a general machinist shop but they said they would not work on it because I had already done so (liability) -- so as of now I cannot get the water pump plate/bolt in place so it seems to have made the lower unit un-usable (if you or anyone have any suggestions I am open to hearing them --- I can provide pictures) 

I looked around on line today and and there are two "blown up motors" that have "fully functioning" lower units for sale (1 an hour away, one 2 hours away) that I may try and go see later in the week 

[WRB]

If the helicoil (spring in the threads) is damaged you can pull it out and get a Helicoil tap to case the damaged threads and install a new helicoil. The water pump housing cover doesn’t have a strength function. 
Don’t know what size original threads are? my guess is 1/4-20.

Tom

[TnRiver46]

I’ve bought at least 3  used lower units , maybe 4…….. not good at counting . They were all good to go 

[WaskaCrank12]

@WRB

Thank you for that info........I am going to ask around the neighborhood and see if anyone is open to helping/guiding me with helicoil removal (and then drilling the hole out a bit more to make it a bit wider to then put in a new/larger helicoil in that will allow the bolt to fit correctly and thus the metal plate to fit correctly--- this will be outside of my skill level/knowledge base --- yet you never learn if you don't try !) --- and at this point either it will work or I will need to get a used lower unit. Thank you.

@TnRiver46 thank you for the info --- your reply gives me confidence in purchasing a used lower unit if that is the route I go -- Thank you  !

 

 

[Way2slow]

The are a number of ways you can fix your current problem.  My first thought and easiest is just to file out the holes in the plate and cover to match the miss aligned screw hole.  If you have enough metal left at the edges, you can take that heli-coil out, make a guide plate to correctly hold the a drill bit in alignment, drill the hole slightly larger an install a brass or stainless-steel threaded insert.  There are other ways but would require things you don't have.  TIG welding the hole and just drill and tap it back out is one, but that requires someone than really know how to TIG weld.

 

One other thing, I know it's a little late now but when you are trying to do something like you were doing.  Bolt the housing back on and use it for a drill guide.  Learning how to take a corroded bolt is an essential skill if you work on these things, especially if it has ever been in salt water.  Never trying to break a corroded bolt loose by just applying wrench pressure, it will probably break every time.  You will use a lot of back-and-forth pressure and a lot of tapping with a hammer.  When you get it to move enough to get a gap under the head.  Keep it saturated with Klotz of PB blaster and let it soak a while.

[DinkDonkey30]

You can buy a new lower for that motor for relatively cheap. I believe they are 12-1500. I have a 98 90hp. I would not repower with the older motor. The controls, electrical, and fuel system would all have to be changed. I don’t know what your mechanic skill level is but if the helicoil is a challenge for you , it might be in your best interest to talk to some local marinas about swapping the lower or if repowering is an option look into upgrading to a 4 stroke. I would also look into private non dealer boat repair shops. 

[WRB]

As Kieth noted there are several good thread inserts to look into.

My suggestion was to use a Hellicoil and retap the Helicoil threads and install a one.

Other options. Is pull out the old Helicoil and install a self taping thread inset, only requires an Allen wrench. The threads don’t need to be perfect to secure the pump cover.

Any auto mechanic can do this as it’s a common problem with aluminum block engines.

Tom

[Woody B]

We use time serts for most thread problems.  https://www.timesert.com/

 

You need a straight hole, in the correct location.  As Keith said make some kind of guide for the drill.  

[WaskaCrank12]

@WRB @Way2slow @Woody B @DinkDonkey30

 

Thank you to each of you for your thoughts and suggestions/ideas -- you are helping build my confidence that this can be repaired !

Based in the information provided, tomorrow I am going to take the lower unit to an "engine machining shop" that is located north of me and see if they are willing to take it on as a project -- I feel that the re-drilling/tapping of the hole/having the hole drilled straight to accommodate a new insert is a bit beyond my skill level/tools I own level/my confidence level -- I believe on the first attempted fix some of the broken off bolt is still wedged in to the insert area and that might be a bit tricky to remove (I am sure a skilled machinist/mechanic with the correct tools will have the expertise needed to complete the job correctly).

Thank you ! I will let you know the outcome

[WaskaCrank12]

Update as of 06/05

@WRB  @Way2slow @Woody B @DinkDonkey30

Today I stopped by 3 machine shops and a marina/dealer -- two of the machine shops are "engine machine shops" so I was hopeful -- all three declined to take it on as a project, all said "aluminum is fragile and extremely difficult to work with" -- one said because I had already tried they did not want the liability of taking it on -- one said to maybe try and shave the metal plate back a bit so the screw would fit -- the dealer (who I went to last) recommended two of the three places I had already been to -- so, back to square one -- I have spent the last few hours watching Danger Marine and other motor "broken bolt in aluminum" videos -- so tomorrow I am going to try the following:

 

--pull out the heilcoil -- spray the insert area with PB Blaster and let it sit for a while -- go to Harbor Freight and get a "burr extractor" and new size heilcoil to fit the original bolt size -- and then try and back out the piece/s of the old bolt that are still in the insert area with the extractor -- if that is successful I will then look to put in the new heilcoil and go from there -- if it is not successful then I will try and file the metal plate back a bit -- any thoughts recommendation are welcome !!

 

Right now it's an unusable lower unit --- so I feel it's worth the risk for me to try these things (even though this is well out of my comfort zone) --- no risk, no reward --- the worst that can happen is I am back to square one --- if that happens then I will search for a used lower unit

 

[Way2slow]

I have to say, it sounds like you really botched the first repair attempt, especially if you tried to put a heli-coil in with part of the broken bolt still in there.  You should have never tried that.  

I'm going to give you a little broken screw 101.  First using a sharp center punch try to get and starting point as near center of the broken screw as possible.  Using a sharp, 1/8" drill bit, drill a pilot hole as near center as possible.  Start slowly and angle the drill as needed to get the bit in the center.  Use max drill speed and light pressure as you drill the center straight down, If you use slow speed, the bit might bite into the metal and break the bit off in the hole.  If the bolt is has work hardened, you might have to use a slower speed on the bit to get it to cut, just be extremely careful if you do.  Getting that broken bit out will open another whole bucket of worms because it's too hard to drill so has to be broken out.  Once you get your pilot hole, being careful to feel when it goes through the bolt, and you don't drill all the way through into the lower unit. Now you want to go up to the next larger bit and start making the hole bigger, still angling the drill as you first start to help work it toward the center of the broke bolt. Once you get the hole large enough you can start seeing the threads on the bolt, us a small, pointed punch and start working it between the aluminum hole and the steel bolt, breaking, crushing the bolt into the hole.  There are easy-outs you can try once you get close but not those spiral tapered, they only make it tighter at the top, it has to be a straight shank, again, be extremely careful doing that because you can break the easy-out off and back to the same problem of trying to break it up to get it out.

Unless there is a fair amount of good metal below where you have already botched that hole, you WILL NOT be able to use heli-coil to install the factory size bolt back in.  That's why I said you might be able to install an insert, they require a little larger hole that a heli-coil and you might have enough metal left to hold one of those.  The only option for a heli-coil is going to be using one larger than the factory size.   Your heli-coil options are probably going to be a #16 or #18 machine screw if you can find one or something in a metric that is just a little larger and drill the pump housing out a little.  I doubt you have enough metal to go as large as and 5/16" bolt.  That's why I said and insert is probably your best option if there is not enough metal left below what you have screwed up.  If by some chance there is enough, then do the heli-coil deeper and use a longer bolt.  Just be care you don't drill through into the gear case.  If by chance you do, don't fret it too bad, just make sure you put a dab of silicon in the hole before you install the bolt to seal it.  If all else fails, you can just drill the OEM hole deeper, getting below all the botched hole junk, using the water pump housing and plate as a guide.  If you do, make sure you go a little at the time with grease on the #7 drill bit to catch the metal shavings, so they don't go into the gear case.  Tap it to the with a 1/4-20 tap, if that's the size of yours, again, keeping grease on it to catch the shavings.  Then just use a longer bolt.  Let me say, I've never done that with an OMC gear case, so I don't know how much metal is below the OEM hole and there might not be enough to get a useable length of threads.  So you are on your own if you try that one.  

I've never use this but I know a couple of people that say it saved their butt, so might be worth trying if you see no other options.  Loctite Stripped Thread Repair Kit, 12.9mL, Gray Form-A-Thread 236382 | Zoro

Like I said, there are tons of ways to repair it but I have done this crap for most of my 77 years so I have a little more experience on how to fix an "O-Sh**!"

[WaskaCrank12]

Hello @Way2slow @WRB 

 

Thank you for making the time and sharing your expertise with me -- no doubt the first attempt at fixing this did more harm than good -- I fully appreciate your detailed layout of how to approach this -- I have printed out the info you have shared and will use it as a guide as I work on it -- this is my first time working on something like this and having people like you share their expertise with me is invaluable -- as they say "success leaves clues" and you have had success in navigating issues like this and I appreciate you sharing your "success clues" with me -- 

There is about 20 % of the bolt left in the insert area, the bolt is not whole, it is only a small sliver of it on one side of the insert area, so job number 1 is to get that out -- then I will go with what you recommended (an insert vs. a heilcoil) as that appears to make the most sense given that I would rather use the original size bolt if at all possible 

Thank you again -- I will provide progress updates as I move thru the process  

[Way2slow]

You should be able to take something like a hardened scribe (probably not one of those Harbor Freight junks) or similar that has a long sharp end on it and slowly tap it between the broken bolt piece and the aluminum housing and get it started pulling loose from the wall of the hole.  Once you get if separating you can keep working it and eventually get it out.  It will take time and patience, if you try too hard or get frustrated it's just going to lead to more problems.

[detroit1]

Thanks waytooslow for always sharing your knowledge with all of us. It's greatly appreciated.  

[DinkDonkey30]

To add to what way2slow said use masking tape on the drill bit to mark desired drill depth . Ie if you want to drill 1 inch go up 1 inch from the tip of the bit then wrap tape around bit so you know visibly when the tip is at the max depth you want to drill. 

[MN Fisher]

38 minutes ago, DinkDonkey30 said:

To add to what way2slow said use masking tape on the drill bit to mark desired drill depth . Ie if you want to drill 1 inch go up 1 inch from the tip of the bit then wrap tape around bit so you know visibly when the tip is at the max depth you want to drill. 

I've seen too many times it go past the tape...get stop-collars...much more secure and accurate

 

[DinkDonkey30]

Idk I’ve worked as a diesel tech since 2011 and built race cars as a hobby for about 20 years. Tape has always been my go to. Stops can be a hassle depending on space and stuff in my opinion but that’s just me. I’m probably also a little more familiar with my tools than others due to time using them and experience overall so that makes a difference as well. 

[WaskaCrank12]

Update - 6/7

@Way2slow @WRB @Woody B @DinkDonkey30 @MN Fisher

 

Ok....a slow tedious process, and I kept looking at Way2Slow's advice of "take your time and be patient".....because it was a literal grind....I ended up purchasing multiple sized Irwin "extractors" (Way2Slow I took your advice and avoided HF) and ended up using all three of them at various times.....between yesterday and today it was probably 4 or more hours of work/grinding the stuck bolt down (I had tried to pry it out yet it became clear to me that the metal from the bolt was basically fused into the aluminum threads in the insert).....finally a piece of the bolt came lose and fell to the bottom of the insert, I used tweezers to get it out of there.....then, and my neighbors already think I am a bit zany, I ran out of the garage beating my chest and yelling YEAH !!!!!!

The insert area is not perfect, a bit damaged from the initial try at the fix and from this work.....but no damage to the bottom (I ended up using tape to mark it, yet I appreciate @MN Fisher suggestion of the stop collars)....now when I put the metal plate on and the cover on it lines up and I can put the bolt in.......BUT....I do need to now figure out if a "Time-Sert" or Helicoil will work best (I think the aluminum around the insert area is now worn down too thin to try and just tap new threads into the aluminum/insert area).....so there is clearly quite a bit more to be done....but always good to celebrate a small victory in the process.....

Any additional suggestions/information is appreciated !

Thank you to all who have contributed to this, specifically @Way2slow , I literally could not have gotten this far without you !! Thank you !!

[Woody B]

A time sert requires a bigger hole than a heli coil.  What size is the bolt?  I may have what you need to install a time sert.

[Way2slow]

I think a threaded insert is going to be your best option for repair if you have destroyed most of the metal in the upper part of the hole.  If insert feels loose or you don't think there's enough holding it. get you one of those thread repair kits I posted the link to above.  I know it's expensive, but it's a lot cheaper than a lower unit.  Don't use a release agent on outside of the insert, but do put some on the inside, just in case you get some on the inside threads, you do not want to do that.   I've done this a few times with Devcon but Devcon is super expensive now.  Let that cure the specified times and if done right, it will hold just fine.  

If you do try to go back with a heli-coil, use red Loctite on the thread you cut to screw it into, just don't put so much it gets all over the inside part of the thread.  It only takes "ONE DROP" and spread it around a little, the insert will take it on down into the hole as you screw it in. 

[WaskaCrank12]

Hello @Woody B @Way2slow @WRB

The bolt is 1/4-20 size - I have 4 new bolts that came with the Evinrude water pump kit I purchased. 

During the course of grinding out the insert area (to get the broken bolt out) the insert area did become larger and wore down/damaged the majority of the original threads - so I do believe a "threaded insert" (that @Way2slow mentioned) will need to be used - later today I will look online to order one.

Yes, the Devcon looks to be about $100 - could I use a JB Weld ? Or are there other options ?

You had written that I should not use a "release agent" on the outside of the insert (yet I should put it on the inside of the insert) -- I am not sure what a "release agent" is -- could you please clarify that for me ? (I am guessing it might be anti-seize ?)

Again, thank you to each of you for making the time to share your expertise with me !

[WRB]

The Heli Coil 1/4-20 insert OD is .291 so use .291 use letter L drill and thin wall 1/4-20 stainless steel insert. The coating is needed to form a barrier between the aluminum and SST insert to prevent corrosion not strength. Depth of hole needs to be determined before you start based on original bolt length and thread insert. You don’t want to drill any deeper the original hole.

You may want to practice on a piece of aluminum before working on the lower unit.

Tom