1996 Johnson 150 - starts great - runs sometimes

[BassinBob]

I have a 1996 Johnson Faststrike 150. My problem seems to be a flooding problem. When I first put the boat in the water (or on the hose in the yard)it fires up fine. When I try to go it dies and refuses to start. Occasionally it will crank up again, I can plane out (sometimes) then BLAAA it dies regardless of rpm. The plugs are dripping with fuel. Oh, and sometimes I wait an hour or so and it cranks up and runs great all day! There is a lot of smoke as well. I have new plugs, wires and coils. Can the VRO Fuel Pump be pushing too much fuel? Powerpack maybe? Any help anyone can give would be tremendously appreciated.

 

[OBJ]

Re: 1996 Johnson 150 - starts great - runs sometimes

Hi Bob....let do the easy stuff first. Do a compression test and make sure all cylinders are within 10% of each other. Pull the hood and tilt the engine a little forward. Pump up the primer bulb. Does the bulb pump up firm? If not, replace. Note any carb that may have gas coming from the throat. Thats a sign of a bad needle or miss adjusted float. Look around the carb bowls for leaks. The plastic bowls do sometimes warp and leak pretty good. Do you see any fuel in the water when it idles? Check all fuel connections are tight. Replace any snapper clamps that are broken. You'll see a lot of these around the VRO pump. Check any fittings on the block that may be lose and sucking air. With the engine at idle, dab some soap solution around the VRO pump where the front pump section meets the middle section. The front section is the motor section. Any leak here can cause you trouble. It runs of the pressure and vacuum created by the engine. When was the last time you decarbed the engine? If you are a do it yourselfer, get a service manual for the engine. Lots of good stuff in there. This is a start. Keep us posted.

 

[BassinBob]

Re: 1996 Johnson 150 - starts great - runs sometimes

All cylinders have pretty decent compression and they are close to eachother. The primer gets firm and it does not loose its prime. I changed the fuel line to the engine from the primer and the primer ball two years ago.<br /><br />As far as fuel at the carb throats all six have some fuel sitting on the bottom of the throat. There is also gas pretty much all over the VRO fuel pump but when its running I can not see any fuel coming from anyplace.<br /><br />At idle in the water there is a lot of fuel it the water around the motor - as evident by the rainbow slick. And, when it does start up again, tons of smoke like it was flooded and had a lot of fuel in the cylinders.<br /><br />I've been pretty lax in the decarb department lately, been 2 seasons. Would carbon build up cause this problem?<br /><br />Since the motor is out of warranty for a long time now I reckon a shop manual would be a very worthwhile investment.

 

[clanton]

Re: 1996 Johnson 150 - starts great - runs sometimes

Check the coils and power pack.

 

[ICEMAN]

Re: 1996 Johnson 150 - starts great - runs sometimes

I would strongly suggest a factory service manual. Sounds to me like a fuel delivery problem. There should be a few VRO pump tests in the book. Your pump could be leaking, you mentioned the VRO pump having fuel on it, it's possible the pump is leaking fuel when the motor is not running, and sucking air when it is. If it's sucking air, the pump will try to make up by pumping faster, sending more oil into the motor, giving you the smoking condition on restart.

 

[BassinBob]

Re: 1996 Johnson 150 - starts great - runs sometimes

I looked it over real good just this afternoon. What I found was that there was a leak at the fuel line feeding the left carbs. I never noticed it but when I cleaned it up and cranked it over it came out pretty good - then stopped. Maybe its drawing air there when I try running and it pulls more fuel and floods out? I'm going to take it out tomorrow and see what it does. Since I have a bass tournament on Lake Seminole this weekend it would be real nice to have my boat back.<br /><br />Another question for all the experts out there. I was told I have one carb running a little lean. All I can see is a single adjusting screw (at least I think that's what it is) to the right of the throat (small brass looking screw). How do I make that one carb run a little richer?<br /><br />I really appreciate all the good advice everyone is giving me, I was about at wit's end with this. I'll let ya'll know what happens tomorrow.

 

[OBJ]

Re: 1996 Johnson 150 - starts great - runs sometimes

Well Bob...at least your on the water. Most of us are still shoveling snow with more to come.

 

[BassinBob]

Re: 1996 Johnson 150 - starts great - runs sometimes

I've done my time in the snow also, from New York state to Alaska, so I know exactly how you feel.

 

[BassinBob]

Re: 1996 Johnson 150 - starts great - runs sometimes

OK, After taking the boat out this moring this is what it did.<br /><br />Started up great. Dropped it into gear and eased forward - all was good. Started pushing up onto plane and it died. After a few minutes I tried it and it sneezed once, then the next time it fired up and ran great for the rest of the morning.<br /><br />At one point, running between 65 and 70mph @ 5500 rpm it felt like it stuttered a little, then kept running nice and smooth. Tach was steady at 5500. Even when it flinched that one time the tach never wavered the slightest bit.<br /><br />I did not prime the motor at all today, not first thing, not restarting after it died.<br /><br />If I was in need of decarbing the motor would that cause this type of problem? I really need a dependable motor again and $9,000.00 is not an option <br /><br />Oh, and I caught a few bass while I was on the water as well. Just had to throw that in there

 

[jim dozier]

Re: 1996 Johnson 150 - starts great - runs sometimes

Did you fix the leak in the fuel hose by the carburetor you found? Who says one of your carburetors is lean, and what did they base that on? My point is that if its running lean at mid-range or WOT, something supplying fuel is clogged and needs to be cleaned or you have a leak and air is replacing fuel. If it is running lean off idle it may just need an adjustment of the idle mixture. Mid-range and WOT jetting doesn't need to be replaced/adjusted, just kept open and fully supplied with fuel not air.

 

[clanton]

Re: 1996 Johnson 150 - starts great - runs sometimes

Check power pack, timer sensor, coils.