'75 Johnson 115hp back-fireing

[ohyeah829]

Ok, new problem....I've had my '75 Johnson 115hp engine idle for the winter. I winterized it by filling the gas tank and adding the de-waterizier....Is there anything special that I should have to do to get it running, now? Because, I can get it to crank, but it is backfiring now. Both when in neutral and in gear. The only thing that I did over the winter is replace the spark plugs. <br /><br />I have noticed that if I put my finger on the spark plug wire while the engine is running, it will shock me, duh...but I can feel it sherper when it backfires...like a needle poking. This is probably usual, huh??<br /><br />Any solutions?

 

[ohyeah829]

Re: '75 Johnson 115hp back-fireing

Also, the lower unit seems to be smoking a little from the holes in it. It seems to be hot, is this normal? I am running it using a water hose.

 

[ezeke]

Re: '75 Johnson 115hp back-fireing

Is it really backfiring? - back through the carbs?<br /><br />The only way I know that can happen is if the reeds have failed.

 

[ohyeah829]

Re: '75 Johnson 115hp back-fireing

Ok, it sounds as if it's choking...every time it does it white smoke comes out the exhaust on the prop. It's not actually making the loud *k-pow* sound like a truck...hope this explains it a little better.

 

[reeldutch]

Re: '75 Johnson 115hp back-fireing

try it with a fresh batch of gas and tcw3 oil.<br />does the motor sneeze? or cough?<br />that could be a lean condition.<br />but my first gues is contaminated fuel.<br />check also your compresion to make shure your headgaskets are still fine.<br /><br />good luck

 

[ohyeah829]

Re: '75 Johnson 115hp back-fireing

More of a cough...seems to shake as if just for a second, trying to die. After idling for a few minutes, it will actually die. <br /><br />My thought, also. So, I will try a new tank of oil. What do I need to check the compression? And, where can I get it? Thanks!

 

[ohyeah829]

Re: '75 Johnson 115hp back-fireing

Any ideas on why the lower unit would be running warm? Or, is this normal? Thanks for your help!

 

[ezeke]

Re: '75 Johnson 115hp back-fireing

There is a rubber grommet (part # 0314937) between the gearcase housing and the exhaust housing. It needs to be in place for back pressure and to direct the exhaust out through the prop.<br /><br />Your problems may both be related to this.

 

[ohyeah829]

Re: '75 Johnson 115hp back-fireing

I'm not sure what you mean...kind of a rookie here. Sorry. In my terms? What do I need to look for and what can I do to fix it? Thanks for the reply!

 

[ezeke]

Re: '75 Johnson 115hp back-fireing

When you remove the gearcase for water pump repair, the exhaust connection (behind the water pump) detaches from the exhaust housing.<br /><br />The rubber gasket at this connection is sometimes damaged, or does not fit properly when replacing the gearcase. It may also just deteriorate over time. <br /><br />You can put a little tape or something to hold it in place while you tighten the gearcase up.<br /><br />Without the grommet, the exhaust gases feed into the rest of the housing and can possibly even return to the engine compartment.<br /><br />See the Exhaust Housing drawing on the BRP parts site and look at #26 on the diagram. <br /><br />This is only a $10. part so don't panic. web page

 

[JB]

Re: '75 Johnson 115hp back-fireing

Duplicate post.