Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stroke

[blugrasmaniac]

I am in a bit of a pickle. I just got a 1994 Evinrude V6 175HP two-stroke, and it was running fine until someone added gas, but no oil...

Predictably, the motor seized, and now I need a little help getting it repaired. I have a fair amount of mechanical experience - mostly on cars, but haven't replaced a piston before.

Just a few questions for now:

1. Only two pistons are seized; however, does this mean that they are "ok"? What about burning - should I be concerned about discoloration on the top of the piston?
2. Assuming this engine has never been rebuilt, does the cylinder need to be bored out, or does it have a sleeve that can be replaced?
3. Finally, will I need to remove the entire powerhead? If so, will I just need head gaskets or a complete powerhead gasket set?

Keep in mind this engine ran great just prior to this - so I'm not looking to rebuild more than necessary as a result of any damage incurred.

Thanks for your time!!

 

[GA_Boater]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Have you opened it up yet. It's impossible to predict needed parts until you tear it apart. It may have been running great before, but as soon as it was run to the point of seizure with no oil, all bets are off.

 

[racerone]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Powerhead needs to come off. Then take it all apart for inspection.

 

[Bosunsmate]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Dont buy a thing until you have it apart. You may be lucky and its just the rings that a causing it to stick, if the bearings have come out they will damage the crank and everything else they get stuck on pretty severly.
Id just get a whole new gasket set, it doesnt cost much compared to the benefit you get from having a new set in there.
The main cost you will be up for is a new crank and if you get lucky and thats ok then the pistons will be your main cost. I normally put in second hand ones, im not that fussy on getting excellent compression just a good reliable runner.
Removing the powerhead is probably the most time consuming thing you will need to do especially if its a salty.
Drop the LU first

 

[daselbee]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Well....prep up for some work.
To answer your questions...
1. You should replace them all. All of them ran dry of oil. Don't forget that the bearings ran dry also. Look all crank surfaces over for bluing and heat discoloration.
2. It can be bored. It also has sleeves that can be replaced if one is too damaged to clean up with boring.
3. You will have to remove the powerhead. It will have to be split in half (opened) and completely stripped of all parts in prep for the machine work necessary.
You don't necessarily need to get a whole gasket set, you can buy them individually. The whole set will come with gaskets that you don't need. The whole set might not include gaskets that you DO need, like the powerhead to adapter gasket.
Do not scrimp on gaskets by buying aftermarket brands. Use real Evinrude gaskets. They are better quality.

Be prepared for pitfalls...the biggest one in my book is broken bolts. Head bolts, small 1/4-20 fasteners located on the powerhead, and even the powerhead mounting bolts themselves will break. You will need to be very skilled at broken bolt removal.
Start looking for a qualified machine shop that is familiar with boring what is known as a blind hole block. Takes special boring bar.
Get an original OMC/Evinrude manual for your exact year engine. Don't try it with a Seloc or Clymer.

 

[Bosunsmate]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

To answer your other questions, you can often get away with a hone depending on what it looks like and otherwise a bore should do it.
The pistons will probably be stuffed if they are seized, the ring grooves are normally gouged out

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Wow...thanks for all the helpful information, guys! I'll go ahead and start looking for a shop, order an oem service manual, and pull the powerhead, then, and see what it looks like.

I'll post again when I get to that point.

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Drop the LU first

Good information, thanks. Can you elaborate on reason for dropping the LU first?

 

[Bosunsmate]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Good information, thanks. Can you elaborate on reason for dropping the LU first?

Trying to pull the powerhead off normally results in a bit of rocking of the powerhead to break the base plate gasket, you dont want the driveshaft which goes from the crank down to the LU in there while you a doing that

 

[boobie]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

My question would be, why did it run out of oil ?? Were you running on premix or using the VRO ??

 

[racerone]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Lower unit needs to come off for a new water pump impeller. So take it off first.-----No point in putting a rebuilt motor back in service without a new pump !!

 

[James R]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

A word to the wise. If you have no experience with these motors don't try to rebuild it yourself. There are judgment calls to be made that are best made by an outboard rebuilder. Nowhere near the same as automotive. A factory manual is a must if you plan to do anything.

 

[Faztbullet]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

My question would be, why did it run out of oil ?? Were you running on premix or using the VRO ??

That was my question also... as if premix prepare for some major inspections as everything internally go washed with raw fuel . If it has the VRO in use you have other problems.

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

UPDATE:

I've got the factory service manual - good call. It's very informative. This is a saltwater engine, and it has spent a lot of time in salt water. I was thinking while taking everything down that everything sure is coming apart easily. I've not had any bolts or parts that were rusted up or seized.

Well - spoke too early. I found one, and it's bad. One of the lower main bearing bolts apparently spent time soaking, because the head is basically rusted off. It does have a head, but instead of 9/16" hex, it's more like 1/2" and round.

I can post a picture if necessary, but any recommended opinions on how to best remove the bolt. Looks like it might be best to drill through the head - but I'm a little nervous about that. Any better options?

P.S. It was running on premix - except for the last time.

 

[racerone]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Drill the head off.-----Take it apart and use a vicegrip and possibly heat to get the remainder out.

 

[daselbee]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Good to hear you haven't had too much trouble with broken bolts.
Regarding the big crankcase half bolt with no head....there will be no way to do it except center drill progressively larger and larger til the head pops off. Once the head is off, and all the other bolts are out, the crankcase half should pop right apart. If you pry, be very very careful. You absolutely cannot damage the mating surfaces of the two halves. They are sealed with gelseal, and MUST not leak any air at all (through gouges in the aluminum) for the engine to run properly.
The locating taper pin will probably hold it together also. I would just drive it out with a suitable drift, and get a new one.

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

I drilled the bolt - it actually drilled quite easily. I'll have to try to look up the specification on the bolt for replacement, but I expected them to be of a harder steel.

 

[gm280]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

I drilled the bolt - it actually drilled quite easily. I'll have to try to look up the specification on the bolt for replacement, but I expected them to be of a harder steel.

Shouldn't have any trouble identifying the proper size bolt to replace the drilled out one once you get the vice-grip on it and remove it. And remember, unless your motor is built from some crazy space-aged material, you are only going into aluminum. So be careful and only tighten the new bolts to the specified torque specs in increasing increments... A too heavy hand will most certainly strip the threads easily. However, since you are familiar with auto engine rebuilds and have the proper shop manual now, I think you will have no problems rebuilding this OD! Good luck and keep us informed. Post some pictures too. They always help.

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

OK - UPDATE:

Got the crankcase off, and disassembly is complete. Everything is separated and numbered for inspection and reuse where possible. As someone else insinuated above, I am probably a little out of my league here Nevertheless, I'm going to give it a go.

Here's the state of what I found:

• Residual Oil: There was actually quite a bit of oil throughout the parts - with the exception of two pistons and the associated bearings.
• Crankshaft: no visible marks or scratching. Does this mean it's ok, or are there specific measurements that need to be made?
• Crankshaft split bearings: These feel smooth oily - I haven't removed them yet.
• Pistons: 2,4,5,6 all normal color and oily - rings look good (still have sharp edges and no visible scratches)
• Pistons: 1,3 - little to no oil - rings destroyed
• Rod caps: no visible marks or scratching that I can detect. They all had plenty of oil, except for the two. They were pretty dry.
• Rod bearings: hard to say - I don't know what these should look like. They're all pretty loose, but no physical defects that were obvious to me. All were oily except for 1 and 3.

I know this is pretty subjective, and I'll do my best to provide any clarifying information, but I would really like to have some input with your opinions thoughts.


I'm taking the block to a shop for inspection/repair; I'll probably take the crankshaft, too, so they can take a look at it.

Thanks in advance - you guys have given me a great deal of confidence that I'm not entirely on my own here

 

[blugrasmaniac]

Re: Need help getting started - No oil seized two pistons on Evinrude 175 V6 two-stro

Shouldn't have any trouble identifying the proper size bolt to replace the drilled out one once you get the vice-grip on it and remove it. And remember, unless your motor is built from some crazy space-aged material, you are only going into aluminum. So be careful and only tighten the new bolts to the specified torque specs in increasing increments... A too heavy hand will most certainly strip the threads easily. However, since you are familiar with auto engine rebuilds and have the proper shop manual now, I think you will have no problems rebuilding this OD! Good luck and keep us informed. Post some pictures too. They always help.

Proper size is easy, sure - I'm just not sure what grades should be back in it. The bolts I removed were brassy colored like some of the grade 8 bolts, but these bolts had no markings.

P.S. Familiar with auto rebuilds is probably being generous to my knowledge, haha. Familiar is a fine word, I guess - I just haven't actually completed a rebuild. I pulled a head and had it machined to fix a head gasket - that's the same, right?