1975 Johnson 50hp...losing power as soon as it hits water...

barrieboi

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I get it goin in a bucket good....but when i get it in the water and put it in gear it dies or goes really really slow....like 1 cylinder is workin....both have spark carbs were cleaned...what else could it be? please throw anything that it could be.....My son really want s to go fishin this weekend....long weekend....Even a deal on a 60_75 hp would work....This motor now starts and idles fine just when i put it in gear it loses power. :confused: :mad:
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

It isn't really idling fine when its not in gear, you just can't tell because there is no load on the engine. It very much sounds as though you are losing a cylinder. Start unplugging spark plug wires and isolate the bad cylinder and then go from there.
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

we did that......<br />im gettin one plug still wet and one still dry......bottom is still wet....but it has spark...
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

Which one was the cylinder that didn't make any difference when you unplugged it. By stating that the bottom wet one had spark am I to understand that the upper dry one had no spark? If I assume as you stated in your first post that you have spark in both cylinders, and when you remove the plugs one of them is dry that would point to a carb problem on that cylinder. <br /><br />How did you or whoever clean the carbs exactly? Most likely you need to remove the carbs (do all at the same time) completely disassemble them, soak them overnight in carb cleaner, replace the float valves, blow the jets out with compressed air, and reassemble with new gaskets.<br /><br />Also, I wouldn't run it anymore until I get it fixed because the dry cylinder may not be getting oil if its not getting fuel.<br /><br />It is also possible that the wet cylinder is the bad one because it is flooding out (stuck open float valve), which is why I ask which one is not working.
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

Remove the airbox from the carbs (if there is one) and watch the carb throats while its running. Does there seem to be gas puddling in one of the carbs? The wet one? Try sticking 2 fingers in the throat of the dry one while its running and see if it picks up, if it does that one is running lean. If you do this on the wet one does it have no effect or make it worse? If so that one is running rich, see carb rebuild above.
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

they boith spark.....both get fuel....cleaned carbs quickly...but the guy who did it works on his stuff regularly....just no boats....both spark i think its flooding out the bottom too...but he says no it cant cause carb is fine....how would i know if its gettin oil.....thanks jim i appreciate this.... :
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

You can't clean a carb quickly, I don't think. I don't know what he did. You have 2 similar posts going on this engine at the same time.<br />Its either too much fuel in one cylinder or not enough in the other, both of which are caused by crud in the carbs. Barring a lack of compression and something seriously amiss with the pistons, it probably the carbs. A common thread in many posts on this forum is inadequate or incomplete carb cleaning/rebuilds. People describe symptoms indicative of carb problems and say the "carbs have been cleaned" which may mean <br />1. Somebody looked at them.<br />2. Somebody sprayed something on them.<br />3. Somebody put something in the gas.<br />4. Somebody took the carbs off and did something to them.<br />5. Somebody removed the carbs, completely disassembled them, replaced the float valve, soaked them overnite in carb cleaner, and blew them out with compressed air.<br /><br />It is usually 1-4. I think the operative word here is "just no boats" in your mechancis resume.
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

lol...ur probably right jim what do i soak it in?<br />what else do you suggest.....taking it all apart...
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

They sell carb cleaner in buckets at the auto stores. Just remove the rubber and plastic parts before soaking. Get a rebuild kit for your carbs.
 

JB

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

Barrie.<br /><br />Go back to Jim's first reply.<br /><br />Pull the spark plug wire off of the plug when the engine is idling in the tank.<br /><br />Does the engine die or is there no change?<br /><br />If it dies that cylinder is making power. <br /><br />If there is no change that cylinder is dead. If the dead cylinder has good spark, then proceed with overhaul of that carb.<br /><br />If you do not have and use a manual you will be on it a week and still not have a good running engine. Get a manual. Then work on the engine.<br /><br />Good luck. :)
 

Chinewalker

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

A quick check for carb problems... Fill a spray bottle with fuel mix (cheap plastic won't work, use a metal one from the hardware store) and spray it into one carb at a time while the motor is running. If it picks up speed or smooths out, you've got a starvation problem... <br />- Scott
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

we tried to pull of plug....one time it did nothin next time it lost power....think it power on and off...u know what i mean....whsat do you all think?
 

JB

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

^
 

jim dozier

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

I think the plug you pulled that did nothing is the cylinder that you want to concentrate on. The plug you pulled that killed your engine is the good one. Now you just have to review the previous posts and determine what's wrong with that cylinder.
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

thnks guys im gonna go try this out......wire for plug was all rusty on my bottom coils....sounds better...think it could still use power though?????who knows....its older......put new plugs changed wires...sounded like it was on 1 cylinder until it warmed up then it kicked right in...?????sound right?<br />thnks for the tip jb to get answers instead of reposting....
 

barrieboi

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

hi guys well my boats is runnin fine now but then today while i was out it just stopped like i hit so0mething? Almost like a bolt or screw is caught somewhere?<br />Anyone know whats up?<br /> Only happens in gear....jumps then stalls..
 

SeaMasterZ@aol.com

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Re: 1975 Johnson 50hp...losing power as soon as it hits water...

is a float valve included in the rebuild kit? the kit costs something like 20 bucks, would that also include the valve? I forgot to ask the counter guy, who had me on hold for 45 mins looking the prices up<br /><br />thanks!
 
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