Johnson experts chime in...help needed...

[mamm7215]

I bought a boat with a 140hp Johnson. Didn't know much about boats/motors and it ran so I thought "great". Turns out it's a 140hp power head on a 90hp leg/body. It's been rebuilt with .030 pistons and rings and the rings are broken in the starboard lower cylinder. I can redo the rings and rehone no problem but digging in further I noticed I've got 2 double barrel carbs on the motor. In reading my manual it says that 140hp power heads should have 4 single barrel type 4 carbs. I don't even know how this went together and ran but is it a big/expensive job to get the right carbs on? Even worth it? Leg seems good and the motor does run well but I could be starving the motor with fuel/oil if the carbs aren't right.
Also, is there any way to tell what year the power head is?
Thanks.

 

[Pokertrampp]

Re: Johnson experts chime in...help needed...

There should be a stamp on the motor with the Model number, it is usually on a round freeze plug looking item on the aft side of the motor. it will be similar to "J120TLCC" the "CC" part indicates the year, in the example it would be 88.

 

[jtexas]

Re: Johnson experts chime in...help needed...

What year motor? It does sound like a 90hp carb. You sure it's not a 140 cowl on a 90 powerhead?

If you're using a seloc, set it aside and get the factory shop manual. Seloc doesn't know what kind of carbs my motor has either (although they did count them correctly, at least).

 

[mamm7215]

Re: Johnson experts chime in...help needed...

There is a stamp plate on the motor mount attached to the lower section. That number is J90****, which tells me it's an 82 90hp motor with tilt/trim. Is there another one actually stamped on the head as you describe? I'll look later. Also, I think some early 140's had 2 double barrel carbs. I'm doing some reading now to find out. If anyone knows for sure, please chime in.

 

[ezeke]

Re: Johnson experts chime in...help needed...

Two carburetors on a 140 means it is a crossflow, built before 1985. There is no way that you can make a crossflow into a loop charged motor, so it is what it is.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

Ok, thanks. So a looper would have the 4 type 4 carbs and a crossflow is a 2 double barrel setup. Thanks. So what gaskets would I need to do just a ring job on the one cylinder, provided it's not too damaged? Is the whole power head going to have to come off or can I do it on the motor? I have a CD complete factory manual coming, my Seloc manual is pretty thin on good info, I've found...

 

[ezeke]

Re: Johnson experts chime in...help needed...

You need a gasket kit. You have to pull the powerhead and disassemble the engine. http://www.iboats.com/mall/partfind...gd_poid=242608&gd_row=48&**********=495413911

You need a service manual for your engine, whatever parts are bad or missing, new screws for the rods, and two carburetor kits.

If you don't find out what caused the ring to catch, it will happen again.

I will be surprised if you find a model specific factory manual on CD, but would like to know where to get it if you do.

 

[Pokertrampp]

Re: Johnson experts chime in...help needed...

There is a stamp plate on the motor mount attached to the lower section. That number is J90****, which tells me it's an 82 90hp motor with tilt/trim. Is there another one actually stamped on the head as you describe? I'll look later. Also, I think some early 140's had 2 double barrel carbs. I'm doing some reading now to find out. If anyone knows for sure, please chime in.

yes, there should be a freeze plug looking item on the block that will have the model number.

 

[d.boat]

Re: Johnson experts chime in...help needed...

yes, there should be a freeze plug looking item on the block that will have the model number.

I just want to repeat this - before you go a step further, you really need to verify what powerhead you have on there.

As you've seen, there's a positive ID on the leg. But, the powerhead could be completely different. I had a professionally remanufacured engine that had mix and match parts that involved a powerhead that was different than the leg that was different than the electronic parts that was different than the cowling. Very difficult to work on until all this was figured out. It was sold to me as a 175 (which it said on the cowling), but was really a 235 powerhead on a leg from a different engine and a different year. I was the, I believe, third owner after the re-man and therefore the history given to me was pretty much non existent. It was just advertised and sold as a rebuilt 175 which it looked like to the untrained eye. Since it started and ran well, I bought it. I encountered the mystery the first time I went to buy a set of plugs when the astute parts guy actually walked out and looked at the engine in order to get the info he needed to input into his computer to identify the correct plugs (required in his parts system, I guess). thus the adventure began....

So, verify what you actually have. Sometimes you really need to search for that model number on the powerhead. Have faith that it IS there and just keep searching until you find it.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

EZEKE-There's a marine supplier near me who can get all the parts I need, I didn't think about the carb kits, might as well do them while I'm in there...I already have the Seloc manual like I said. I wouldn't recommend one other than general knowledge but that said, it's "ok". I just ordered one from somebody on ebay: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250644118419
it seemed worth a buck.
D.BOAT-Yes, it seems that's exactly what I'm looking at here, a mix 'n match engine. I will absolutely track down the engine number. The only saving grace at this point is that I've had it out a few times and it does run really well, when it runs...
I believe the reason the rings may have caught is the original rebuild wasn't done very well. There's 3 small dowel pins on each ring that hold the rings from spinning on the piston. If one of these slips back in the hole, the ring will spin and catch on the exhaust/intake ports. This will break the rings. Hopefully this is all it is and there's not too much physical damage in the sleeve or inner engine. If not, it will be a simple tear down/hone/rebuild.

 

[ezeke]

Re: Johnson experts chime in...help needed...

The CD manual is a not-too-well-disguised Seloc manual.

 

[ezeke]

Re: Johnson experts chime in...help needed...

The engine should have a nickel sized aluminum convex welch plug on the top of one of the cylinder banks. If it's not a replacement engine, it may have a model number on it, along with a serial number.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

The CD manual is a not-too-well-disguised Seloc manual.

D'oh, well there's a moneyback guarantee so if it is, I'll just send it back.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

The engine should have a nickel sized aluminum convex welch plug on the top of one of the cylinder banks. If it's not a replacement engine, it may have a model number on it, along with a serial number.

I'll look for this when I get home later. As well as all over the motor to see if anything's there. In this picture, the V heads are separate from the rest of the motor. I'm assuming I won't be able to get to the connecting rods unless it all comes apart. I will be able to check for the severity of scoring with just the cylinder head cover off, I think. That'll be my starting point before proceding, determining if digging in further is warranted.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

Oh, one more quick question. When I've had the muffs on to idle check and flush previously, I noticed that there's a LOT of water spewing out from the lower leg/exhaust housing mid section where the lower leg joins and the joins around where the speedo nozzle is. Is this normal? Should it be more sealed? I have a good flow coming out of the tell-tale. Just wondering about the rest of the motor. I did have water in the gear oil when I got it, changed the gear oil before my last outing but haven't checked since. I guess that's something else I can check tonight.

 

[jtexas]

Re: Johnson experts chime in...help needed...

that joint between exhaust housing and lower unit doesn't need to be water-tight, so water will come out all over the place.

 

[mamm7215]

UPDATE Re: Johnson experts chime in...help needed...

UPDATE Re: Johnson experts chime in...help needed...

Cool, thanks for that info.
UPDATE: Well I can't seem to find an engine number anywhere. There is a number on the welch plug but it doesn't start with J so it's likely a part number. I'll keep looking. I'm including some pics of the cylinder and piston. It appears to be completely shot. It looks as though the ring broke and the piston beat it to pulp. There were actually pieces of ring IN the top of the piston. There's some significant scoring in the sleeve wall as well. It looks like it can be bored but the cylinder sleeve doesn't appear to be wearing even. It's thicker at the bottom of the cylinder and much thinner at the top. Would this be ovality? And does this mean the block is shot?

Heavily pitted head cylinder is the dark one at left.
Right head (upper) is pitted but not scored and has good compression (120)

Chunks of ring embedded in top of piston

Cylinder scored, almost full length of bore

Another score on cylinder wall.

I hope these pics aren't too large, I can resize if they are. I'm a little at a loss right now, has anyone seen this sort of thing before? Fixable? Bear in mind the cylinders are already 0.030 over. I haven't looked at the other side yet but the upper cylinder on the damaged side, though carboned, is in good shape, though it looks like that cylinder has previously had a broken ring as well.

 

[mamm7215]

Re: UPDATE Re: Johnson experts chime in...help needed...

Re: UPDATE Re: Johnson experts chime in...help needed...

Also, the number at the plug at the top of the cylinder is 391226 RPH. I believe this is a 140hp replacement head.

 

[ezeke]

Re: Johnson experts chime in...help needed...

It is a replacement powerhead.

We can see that it is a crossflow engine somewhere between 1979 and 1984. More pictures of the rest of the engine could narrow it down.

You need a new cylinder head.

 

[mamm7215]

Re: Johnson experts chime in...help needed...

That's what I thought. It's a bit dark now, I can get a couple more pics tomorrow. Of what specifically?