johnson 5 1/2 hp seized..now what?

[tfbrown1270]

Hi..I was just given a basket case o/b...I don't know the year or model # but the white case has JOHNSON on the side and a 5 1/2 on the front...its a 2 cylinder and apparently hasn't run in a decade...I couldn't turn it over so I suspected it was seized; when I took off the head and exhaust cover I noted the top cylinder has rust that feels like thick frost, the bottom is better, from the exhaust port side I can see the rings are rusted too.......what now?

 

[Bass Runner]

Re: johnson 5 1/2 hp seized..now what?

Let it soak in marvel mystery oil for a day and see if the piston breaks loose, you can still revive the motor

 

[Solittle]

Re: johnson 5 1/2 hp seized..now what?

After soaking for a day put a piece of wood on top of one of the pistons and give it a rap or two. Let it soak for a few days if it dosen't free up on the first couple of whacks. Marvel Mystery oil is fantastic stuff.

 

[CFronzek]

Re: johnson 5 1/2 hp seized..now what?

You need about 60 lbs. of cylinder pressure to get the motor to start. If the rings don't come loose in their grooves you're not going to get the 60 lbs.<br />Of the few rusted motors I've torn down some required the rings be broken into pieces to save the pistons. Others weren't salvagable. I threw the piston assemblies away, rebored and fitted new pistons. The second option was a lot less work.<br />Before you do anything you should find out exactly what vintage this motor is.<br />Charlie

 

[OBJ]

Re: johnson 5 1/2 hp seized..now what?

Gotta agree with Charlie. Rust that thick with rings rusted in ain't real repairable no matter how long ya' soak them. You might want to check out parts available and cost before you decide on what to do. Post a model number and we can tell you what year you've got.

 

[Paul Moir]

Re: johnson 5 1/2 hp seized..now what?

I've got to go with OBJ and Charlie here; they're likeley right about your one. But I've had _some_ success with lightly honing out rust shadowed bores on outboards that would otherwise be thrown away, and gaining 10-20psi compression by doing it. This is after first getting the engine to turn and then tearing it down.<br />Check the crankcase first though to make sure there's no sign of rust there, and the rings must be free of the piston grooves.

 

[Chinewalker]

Re: johnson 5 1/2 hp seized..now what?

Be VERY careful with any tapping or hitting of the pistons. Tapping from the crown side isn't too bad if you're using a plastic mallet or wooden block, but from the con-rod side can be tricky, as those aluminum rods and their bronze bearing sleeves are very delicate and easily bent/marred. Those rods are getting scarce as there are lots of those motors out that have tossed one of them through the crankcase. The crankshafts generally get scorched when the rod goes. If you've got a good crank and two good rods, then you're already ahead of the curve. <br />- Scott

 

[tfbrown1270]

Re: johnson 5 1/2 hp seized..now what?

Hi...thought I would post to keep you up to date...I tilted the engine up so the cylinders would hold some oil and let it sit a few days with pentrating oil pooled in there...and sprayed liberally into the exhaust port hoping to get some past the rings.....then I took a wood stick about the diameter of the cylinder and whacked the be-jeezus out of it, trying to push the top piston in as it had the roughest bore and I didn't want the rings to slide past the crap on the way up....it moved a 1/2 inch or so after about 50 whacks so I took my dremel and wire brush and buffed off the rust, then I alternated punching one piston in then the other till it broke free, each time I would clean off the rust on the bore so I wasn't using the rings to scrape rust...I think it worked ???????....it turns like butter now, no clunks or grings and the bores are smooth no gouges or scuffs............so where do I get gaskets eyc as all mine are toast...oh and a thermostat and impellor too....thanks again all....Tim

 

[Mantas]

Re: johnson 5 1/2 hp seized..now what?

Still no model number for us? I'm still skeptical that you 'fixed' it. I wouldn't change the thermostat, impellor, or work on carb unless I knew that thing still had good compression. Take it one step at a time so you don't waste money on a engine that needs major repairs.

 

[DJ]

Re: johnson 5 1/2 hp seized..now what?

Get your model# and serial# and see your local John/Rude dealer. They can probably get everything you need.

 

[tfbrown1270]

Re: johnson 5 1/2 hp seized..now what?

hold on......k.....here they are...<br />model #CD21A<br />ser# 0402667<br /><br />thanks<br />Tim

 

[Paul Moir]

Re: johnson 5 1/2 hp seized..now what?

Johnson model CD-21<br />Year 1964<br />HP 5.5<br />WOT RPMS 4000<br />Displacement 8.84 cu.in. = 144.8 cc<br />Cylinders 2<br />Weight 57 lbs. = 25.9 Kg<br />Gear ratio 15:26<br />Spark plugs Champion J6C (was J6J) gapped at .030"<br />Fuel mix: 50:1 originally. If that was my outboard I would use 24:1 in it though.<br /><br />If the head gasket is in any shape, stick it back on and do a compression test. Torque the head bolts to 60-84 inch/lbs. Do the centre bolts first.

 

[tfbrown1270]

Re: johnson 5 1/2 hp seized..now what?

Thanks Paul..<br />I'll do that Its not too torn up...I'll post some numbers...I'll try to sneak into the garage now...(ps; my family is from Parrsboro NS!)<br />Tim

 

[tfbrown1270]

Re: johnson 5 1/2 hp seized..now what?

40 psi bottom cylinder, 50 in the top....I can hear the air getting by the rings.....aaaaaaagh! is there some way to free the rings without tearing the block apart and replacing the rings and pistons?<br />Tim

 

[oldoutboard]

Re: johnson 5 1/2 hp seized..now what?

Tim,<br /><br />You rarely get away with unseizing a motor and not having to make a repair, if there was rust in the cylinder, as you said initally. Email me and I might be able to help.<br /><br />oldoutboard@hotmail.com<br /><br />Steve

 

[tfbrown1270]

Re: johnson 5 1/2 hp seized..now what?

Thanks for all the input.....I don't want to/can't put a lot of cash into this thing so I'm gonna pick up a manual, split the block and see what the price of a do it yourself rebuild will be...is reasonable (>$300 CDN) I'll have a shot at it, otherwise its gonna anchor the end of my floating dock to the lake bottom...

 

[Paul Moir]

Re: johnson 5 1/2 hp seized..now what?

Hey, before you toss 'er in the lake, try selling in parts on ebay. The rods alone will probably fetch some interest if they're in good shape.<br /><br />Finding some oversized pistons for that engine is going to be really difficult, so forget about replacing them. Try honeing it out and popping the old rings back in for a compression test. If you get to something half good, order a NOS set of piston rings. I got mine for less than $40CDN all told. <br />NOS Piston ring suppliers:<br />Twin City Outboards <br />Parts For Outboards <br />Mastertech <br /><br />Good luck!

 

[henning_dt85]

Re: johnson 5 1/2 hp seized..now what?

found a piston for the 4hp 1987, layed in a box in a couple of years, the rings were stuck, so I warmed them up and got it loose ( all of the ring wasnt stuck in groove)

 

[seizedoutboard]

Re: johnson 5 1/2 hp seized..now what?

For some reason my Johnson 9.9 seized-up in storage, never had any storage related problem before and wasn?t prepared to drag it to my dealer get it repaired. Internet brought me too Engine Release. The only product I could find developed for un-seizing seized up pistons.

 

[samo_ott]

Re: johnson 5 1/2 hp seized..now what?

Now that this thread's been brought back, I wonder what ever happened to tfbrown's 5.5?