johnson 140 exhaust

[whalerone]

Hi there.... Hoping I could get some info on the exhaust ports of my johnson 140 1980?? It's been sitting in the garage for close to two years now.

Of the two holes just below the power head, only the one on the starboard side puts out any pressure that I can feel with my hand. Nothing seems to be coming from the port side hole?? Is this normal??

Also, while the engine was idling (w/earmuffs on in the driveway) I went around and pulled each plug wire and replaced (cheap man's check for dead cylinder) and noticed that the bottom cylinder on the starboard side is not contributing. Is this related to the lack of exhaust?

Will be checking for spark and subsequently cleaning the carb with choke cleaner soon. Any other suggestions??

 

[emdsapmgr]

Re: johnson 140 exhaust

You should do a compression test to really understand what is going on. All 4 holes should be within 10% of each other, and probably over 130 lbs each.

 

[tashasdaddy]

Re: johnson 140 exhaust

swap the coil on the bad cylinder with a coil from a good cylinder. if the problem follows the the orignial coil from the bad cylinder, replace the coil with new one. on muffs all the exhaust if going out the prop.

spray choke cleaner is a waste of time and money. the have to be removed, dismantled and clean. and reassembled with kit for each carb.

replace the impeller.

 

[whalerone]

Re: johnson 140 exhaust

Thanks for the help guys.

I see now that the exhaust thing isn't an issue after realizing that it was all shooting out the prop when using the muffs.

On to the dead cylinder... I checked for spark and found plenty of juice. Then I checked compression all round.... 130psi on both cylinders port side... 122psi on the upper stbd cylinder..... and a big fat zero for the bottom cylinder!!!

Next step?? Pull the head and check for bad valve?? How exactly will i be able to tell? What should I be looking for???

Also, is there a particular pattern/sequence for removing head bolts??

Again.. any help would be greatly appreciated...

 

[whalerone]

Re: johnson 140 exhaust

this is a bummer!!!!!!

 

[Benny1963]

Re: johnson 140 exhaust

you wont find a bad valve but pull the head on that side and you will see the damage on that cyl .looks like rebuil time
good luck

 

[emdsapmgr]

Re: johnson 140 exhaust

You are headed to a complete teardown and overhaul. You can pull the head, the exhaust covers and side covers to see what is going on in the bad cyl. Don't be suprised to see pits in the head and top of the piston-if a ring let go. Look for cylinder liner-piston scuffing, even detonation on the piston top.

 

[whalerone]

Re: johnson 140 exhaust

OK... Will be pulling the head and exhaust cover soon. I'll try posting some pics so that the next unlucky guy with the same problem will know what to expect.

 

[whalerone]

Re: johnson 140 exhaust

here we go...............

 

[whalerone]

Re: johnson 140 exhaust

It's funny how things seem to come full circle.... I originally thought that I had an exhaust problem, but it turns out that I really didn't understand how it worked (nearly all exhaust blows out through the prop when running on muffs). Because I didn't know this, it didn't occur to me that there was any difference to running the engine in or out of the water unless it was in gear.

And so in hind sight... I admit to over-reving the engine while on the muffs and there by overspeeding it to the point that I pushed my own engine to fail.

After removing the head and exhaust cover and looking at the damage. I found no rings on the piston and excessive play within the cylinder (duh?)


So here is my next question to the forum... Spend $3K on a rebuild?? Re-power with a new motor for $12k (neither of which I can justify to the wife) Or... I found a 1978 150 Johnson rebuilt two years ago but now has a bad lower unit.. Will my 1980 140 Johnson (good) lower unit be a good swap??

Maybe I'm moving too quickly here??

 

[Theoutdoorsman]

Re: johnson 140 exhaust

I'm not 100% certain, but I don't think your lower units are interchangable. And just for the record, your looking at about $1500 to do it yourself. That is IF you decide to bore all four, replace all pistons new w/ring kits, rod bearings, pollish the crank, rebuild the carbs, new water pump, and so on. You can likely get by with much less money via honing 3 and boring one. It's simply a matter of personal preferrence on the honing and boring. Give the folks at Mar Fab in Sparta TN. a call (931) 738-2819. They are the ones who did my machining and whom I purchased my parts from. They are great folks to deal with and a company many of my local mechanics use to do likewise. Truthfully, it isn't a hard job to do if you are mechanically inclined. It's just time consuming and tedious work. You can always turn to the good folks at iboats for any and all questions you might have along the way. I'm certain someone here can answer just about ANY questions you might have. Dhadley and others helped walk me through it a couple years back. At the time, I was treading on foreign ground!!!! You can spend your hard earned money on another outboard that you are completely unsure of. Or you can spend roughly the same money on the one you have now and KNOW what you've got when your finished with it. Your choice. I wish you the best of luck and would gladly help guide you along the way with anything I can possibly assist you with. I'm confident others will provide all the detail you need, and more. This is, without a doubt, the best forum you will EVER participate in!!! Good luck to you with your decission. I opted to do my own rebuild because of the education I would acquire. And don't laugh at this, but I had no garage to work from at the time, so I rebuilt the powerhead on the dining room floor....... ....... No mess either!!! If you decide to do yours yourself, I strongly recommend you purchase an OEM Service Manual pronto. Stear clear of the Clymers and what not. The OEM is the only way to go!!! Good luck!!!................ ALAN

 

[Silvertip]

Re: johnson 140 exhaust

Yup -- no valves on a two stroke except for the reed valves on the intake side of the engine. Those are not responsible for zero compression. A hole in the piston probably is -- although it could be as simple as a blown head gasket.

 

[whalerone]

Re: johnson 140 exhaust

Are there any other opinions out there on the lower unit swap??? This seems like to good a deal to pass up...

Again... Mine is a 1980 Johnson 140 V4.... His is a 1978 Johnson 150 V6???

For $600.... Am I living a dream??

 

[emdsapmgr]

Re: johnson 140 exhaust

The V4 crossflow lower units are not the same as their V6 big brothers. The V6 units are larger, have a larger propshaft and use larger props. If the V6 has good compression and runs ok, it could work out. It is not hard to find good, used lower units as replacments. Check ebay. Even though there is only 10 hp difference, you won'd believe the difference in torque/power. The V6 will burn more fuel. You should be able to use your same controls/cables.