1996 Johnson 6hp won't idle

[Sherman]

Seem to run fine at high rpm. Will not idle at all. I have cleaned the carbs and installed new kit, changed plugs and checked spark (jumps 7/16 no problem). Pumping the primer bulb does not help. I have to choke it every time even when hot to get it to start. The compression seems low at 89 & 92 warm. I was about ready to pull the head but I thought I better check with you first about any ideas and what the compression should be. My factory manual does not give a compression number just the percentage difference from cylinder to cylinder. Thank everyone for any help.

 

[CATransplant]

Re: 1996 Johnson 6hp won't idle

Compression numbers vary with the tester and the conditions under which you tested. Your numbers should be OK, since the engine runs fine at WOT. They're close enough together.<br /><br />Your problem is no idle, and it sounds like a fuel problem. Re-check the low speed circuit. You could have an air leak anywhere in that area, or a fuel blockage. I wouldn't pull the head at this point.

 

[Sherman]

Re: 1996 Johnson 6hp won't idle

I recleaned the carb but it didn't help. So I took the head off. Everything looks grate. Put on new head gasket. Still runs only at high rpm. Should it make any difference if I run it without the silencer in place. I am just out of ideas. Help!!!

 

[Sherman]

Re: 1996 Johnson 6hp won't idle

Well the more I work on it the worse it gets. I went through the carb again, took the fuel pump apart but no trouble to be found. It seems to run a little better but was hard to start and it got very hot quickly so I stopped. Not too suprising because now I have exhaust in pulses (I think) coming out of the telltale and only a drip of water. I was running it this morning in a trash bin and not on the muffs as I was in previous post. So I pulled out the thermostat and started it but still no water just exhaust out the telltale. I pulled off the exhaust cover and saw no problems. The pistons and rings look great. No holes in the inner plate etc. I guess I will pull the water pump again but it is nearly new. Any help would be very much appriciated!