johnson 20 hp impeller

spycatcher

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May 23, 2013
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Hi all,

i'm new to this forum and hope you guys can help me with my problem.

I have a Johnson 20 hp about 1980 something, the model number is BJ20BFLEND

its been lying outside all winter and now that summer is here, well almost, I've been getting it ready for the water.

It starts without a problem but isn't pumping water, unless I put a hose in the ports and blast the water through

I tried to get the bottom leg of to get at the impeller, undid the 4 bolts, 2 on each side and a stud on the front thinking the leg and shaft would just drop straight out but it wont. it splits with about a half inch gap but when I pull on it it knocks it into reverse and will move no further.

do I keep pulling it until it comes out or is there some other bolt i'm missing

cheers guys
 

Cofe

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Apr 23, 2009
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1,883
Re: johnson 20 hp impeller

Remove the water intake screens and disconnect the shift linkage.
 

spycatcher

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Re: johnson 20 hp impeller

Hi Cofe, thanks for that, i'll give it a go tomorrow

what exactly is the shift linkage?
 

Cofe

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Re: johnson 20 hp impeller

Hi Cofe, thanks for that, i'll give it a go tomorrow

what exactly is the shift linkage?

Once you remove the water intake screens, there is a shift rod linkage behind them. The shift rod is held together by two nuts and once you separate the two, the lower unit will come out. Do not let the lower part of the linkage turn while you take it apart. Turning the lower part of the linkage will adjust the shift height, length.
 

Cofe

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Re: johnson 20 hp impeller

The motor numbers you gave indicate that your motor is a 1992 model. Here are some pics of the shift link connection.DSC00202.jpgDSC00201.jpg
 

spycatcher

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Re: johnson 20 hp impeller

Hi Cofe,

thanks for that, you were spot on

I couldn't get the leg right of because the top rod with the nut on it wouldn't go through the pump but there was enough room to look at it and thankfully it was ok.

i'm going to take the flywheel off it to look at the points, you wouldn't happen to know what the gap should be

cheers
 

Cofe

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Apr 23, 2009
Messages
1,883
Re: johnson 20 hp impeller

If that motor is a 1992 vintage, it would have electronic ignition...no points.
 

spycatcher

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May 23, 2013
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Re: johnson 20 hp impeller

I got the flywheel off and did wonder what was going on, I didn't think they would have had electronic ignition in those days, how do you set the timing then?
 
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