200HP Merc EFI seized??

[Sputs10]

So I've got a remanufactured powerhead from BlackBird, which I'm finding out is my first problem. This powerhead has approx. 50 hours on it since rebuild, but I haven't had any problems until recently. Also, I don't believe I can provide a good SN for the motor as it's ground off the powerhead and the midsection/lower unit is from older motor. A little quick history... the previous motor (a Merc 150 EFI) spun some sleeves and the previous owner was quoted $6,000 to repair, so in lieu of repairing the old powerhead, he essentially gave me the boat. In the Pittsburgh area, there aren't many options and I also didn't do enough investigation and bought a 200hp EFI powerhead from BlackBird and they installed it onto the older midsection since the powerhead's were essentially the same size. Should also mention that BlackBird wouldn't give me a 1yr warranty unless they removed the oil pump, so I've mixed my fuel with oil ever since and I've always leaned a little oil heavy.

Fast forward to now... I was planning a trip to Lake Erie and haven't had the boat on the water in a few weeks. I thought it would be a good idea to ensure the motor was running like normal before driving 3 hours, so I connected up a garden hose (water off) and then turned the key over (more so to check the battery status). Low and behold it started in about 2 cranks of the motor. It only ran for about 5 seconds and I shut it off. I went over and turned the water on and then went back to start the motor. This next sequence all happened within 60 seconds and with water flowing. The motor started right back up and I let it run for maybe 20 seconds, and then for some reason decided to put it in gear and ensure the prop was spinning. So I moved the lever into gear (just above neutral) and walked to the back of the boat and ensured the prop was spinning. At this point, everything looked good, and we're prob 30 seconds into run time. I then moved the throttle lever back to neutral and it seemed to stall. This isn't abnormal when the motor isn't warmed up, so I tried to restart and it just made a grinding sound.

I then removed the cowling and the flywheel cover and the bendix engages the flywheel, but it won't turn. So, I removed the spark plugs to remove the compression, and then tried to turn the flywheel by hand. It will turn freely and easily, but only about 7/8 of a revolution in either direction. Judging by the piston location, the stop point is nearly the same when turning the flywheel in either direction. When it stops, it feels like metal on metal as it's a very hard stop.

I'm a fairly mechanical person, however my knowledge of motors is just enough to be dangerous. Does anybody have any ideas what would cause the flywheel to turn easily, however not be able to make a full revolution? I found a post somewhere that said a sleeve might've moved in the cylinder, but I'm looking for inputs. I plan to tear the motor down tomorrow.

Thanks for your input in advance!

[JOE54]

sleeve would have to rotate a long ways, unlikely, shouldn't cause mtr to lock , pull gearcase first to isolate to powerhead,next pull heads to inspect cyls or borescope , nothing visual ,pull reed plate inspect crank and rods

[SilverFox579]

Might find more help in the 3L forum (what your engine is). Sorry to read of your experience, Blackbird is bad news.

Joe slipped in the one thing I was going to suggest, pull the lower unit.

[JOE54]

OLE SLIPPERY

[OnTRAK]

[QUOTE=SilverFox579;10411259]Might find more help in the 3L forum (what your engine is). Sorry to read of your experience, Blackbird is bad news.

Joe slipped in the one thing I was going to suggest, pull the lower unit. [/QUOT

Since this 200 efi was bolted on the older 150 efi midsection, wouldn't this 200 efi power head be a 2.5L?

[JOE54]

very likely measure bore 3 1/2 is 2.5

[Sputs10]

You guys are correct that it’s a 2.5L. I removed the lower unit today and the motor still wouldn’t turn over. I then removed the head covers and found the middle piston on the LH side (looking from the rear) damaged. The head of the piston has chunks missing from it and the pieces were sandwiched between the top of the pistons travel and the head cover. This debris was stopping the piston from making a full cycle. I’m going to post pictures as soon as I figure out how. From what I could tell, the sleeve looked to be fine. I didn’t notice any scratches or anything.

Leads to two questions...

1) How could this have happened?
2) How do I fix this? Does the Powerhead need removed to replace this piston?

Thanks for the help guys!

[JOE54]

how, many variables, gota come aprt, gonna need a rod also likely (bent), inspect cyl closely, yes will have to come off

[Sputs10]

Pics attached...

[JOE54]

you can remove that piston without tear down, remove reed housing, remove rod cap, push it out, becareful, looks like ring turned hung in port popped off top of pston, locating pin may have came out, pull it and see

[Sputs10]

I'm unsure what a rod cap is, but I'll look at the diagram. Could a new piston be reinstalled in the same fashion, or does is still need disassembled for that?

[JOE54]

rod splits at big end, I would disassemble and have block thoroughly inspected and precision honed or bored ETC...……., its already 20 over, might ask in v6 section for more info on your mtr one down JOE

[EuropeanAM]

Good idea to check out the 2.5L Forum (one more down the list). That's where your engine would be covered.

Is Blackbird not going to take care of this (it certainly appears to be a defective piston, potentially a locating pin failure.

[Sputs10]

Honestly, I haven't even called them yet. I haven't had the best of experiences with them, and just recently had a buddy of mine (board member ranger115hp) in a bind that blew up his 250 pro xs. He paid for a 250 pro xs remanufactured powerhead, but yet they installed a 225. I'm sure you can find his story on here somewhere as well.

From what I'm reading, I have myself convinced that I can at least get this piston removed by myself. I intend to remove the reed housing tonight (I was delaying due to lack of knowledge), and then see if I can access the rod cap to remove this piston. I'm thinking that if I can remove it, I'll be able to inspect the cylinder for damage and then maybe install a new piston. I just haven't figured out how I'm going to install the rings and ring pins yet.

As far as the lack of knowledge goes... this reed housing is located behind the ECM, right? That would be the intake side of the motor I believe. Like I mentioned previously, I know just enough about motors to be dangerous...

Thanks for the help guys!

[JOE54]

1st remove vst from plenum, disconnect harness and link to throttle arm ,related bleed hoses,8 1/4in bolts hold reed housing on, your gonna have to roll mtr to acess rod bolts,12 point 5/16 socket & extension , push it out, remember there is only one way rod cap fits

[SilverFox579]

As far as the lack of knowledge goes... this reed housing is located behind the ECM, right? That would be the intake side of the motor I believe. Like I mentioned previously, I know just enough about motors to be dangerous...

I suggest it would be a wise investment to obtain a genuine Mercury service manual for your engine by serial number before getting too far in this.

[EuropeanAM]

I suggest it would be a wise investment to obtain a genuine Mercury service manual for your engine by serial number before getting too far in this.

+100

Sorry to hear of your troubles- all I can say is that you are certainly not the first (I've actually seen a case where the "core" powerhead was in better shape than the "reman" a customer got).

[Sputs10]

I do have a service manual for this motor. It's almost 800 pages, so I've just printed the section on removing the reed housing.

Thanks for the help guys! I'll be trying to remove the reed housing tonight. I'll supply pics and results later tonight or tomorrow. I'm sure I'll be left with another 10 questions after this next step.

Thanks again!

[Sputs10]

Got the reed housing removed last night, and was able to remove the damaged piston. From what I can tell, it seems the cylinder didn't suffer any damage at all. I couldn't find any scratches in the sleeve whatsoever and the cross hatching seemed to be intact. Comparing this cylinder to the other 2, I couldn't see any differences with my untrained eye.

Attached are some pictures of the broken piston, as well as some pictures of the cylinder I removed it from. Please take a look and let me know if I'd be OK with just replacing the piston, connecting rod, and bearings, and then reassembling.

Also, if anybody has any idea what the correct P/N's are as well as the best source to purchase, let me know.

Thanks again guys!

[JOE54]

you gonna need a .020 over port piston don't know if DON has any may have to source through innerneck ,from pics cyl looks good, without a micrometer in my hand hard to tell actual size though of bore, deglaze cyl slap one in it, new rod bolts , see if it bent rod or replace, new gaskets, torque er down and make some smoke good luck still cant believe it didn't tear cyl up STRANGE