1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

My Johnson 175 is very smokey and has strong gas odor and some visible gas/oil mix dripping out of the exhaust by the pee stream when idling. When powering up, the engine bogs like it is flooded. So, I back off and power up another time or two and then it surges and takes off. Once it takes off, it runs absolutely great in the mid range and on the top end.

The mechanic said the idle jets are probably too rich and to dial them one to one and half turns clockwise, but after looking at similar posts I think I may have a float sticking, as well. Any help on how to resolve or investigate this would be great! If it is a stuck float, would checking the color of the plugs be a good place to start to help narrow down which carb/s are sticking??

Thanks in advance!! Mike

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

tilt your motor up some so that the card openings are pointed down slightly..remove carb cover, then pump fuel bulb..this will tell you if you have a stuck needle valve causing flooding,,..also cold be that a float is out of adjustment..also could be weak spark or bad spark plug..Check and clean your carbs first...get a new set of correct Champion plugs, do a compression test and get a spark gap tester and test spark..should have thick blue streak at 7/16 gap, on every cylinder..post your results

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

Thanks SparkieBoat.

You may have to dumb it down for me a bit more. I have never re-built or torn down carbs. I assume the engine is off when testing the carbs by pumping the bulb and that I am looking for fuel to spill or flow out of the carb or carbs with the stuck needle valve. If I pull the plugs, I should see a black tarry residue on the plug or plugs associated with the suspect carb/s? Can I simply drop that bowl, and look for debris or foreign matter that is causing the float to stick? I dont want to attempt to re-build these carbs and install new gaskets unless absolutely necessary.

Another dumb question - prior to doing a compression test, do i need to disconnect the fuel to prevent the engine from actually kicking over?

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

yes engine would be off when pumping bulb and looking for fuel spill. if you have one plug that is noticeably different from the others it could indicate something wrong with that cylinder. you may just have a fouled out plug, which is why I said to replace your plugs..make sure you use the correct champion plugs, do not use any other brand. the carbs are extremely easy to remove and take apart..be sure to never over tighten your screws. the carbs use seals which are usually reusable, so nothing to buy. you should get someone who has messed with carbs before to help you the first time and show you how to clean out the needle valve and check float adjustment and where the idle jets are..it is really not hard at all..i can do a V-6 carb job from start to finish in about 1 hour, not rushing. and you do not disconnect fuel to do a compression test..remove all spark plugs and disconnect kill switch to prevent arcing. move throttle to WOT position.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

Thanks again for your help and expertise with this. I am going to take a stab at it this weekend, weather permitting and will reply back with results. I run the Champion QL78YC plugs (manufacturer recommended) in it and they are fairly new, but I know it doesnt take a lot to foul one, so I will check and replace them. The mechanic recommended that I dial the idle jets one to one and half turns clockwise since he set the boat up a little rich to run on E10 fuels and I recently started running Non-ethanol 89 Octane in it. I cant imagine that would make that big of a difference, but with the exception of the problem at hand (low-end idle), she ran and sounded better than she has in a year. Great out of the hole, once the bog subsided, and pushing 45 mph at about 5400 rpms. Busted carbs or not, I am leaving the E10 alone for a while.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

be sure if you adjust the idle screws that you adjust them all the same..and if you start over with them make sure you soft set them when you screw them in..if you screw them in tight it will shank them and they will not work well. i doubt that is your problem..usually I have had to adjust those to stop bogging at initial throttle up. I think if you soft set the screws then go about 3 1/2 turns back out that is a good place to start..then turn 1 turn each direction and test and see which way does better. play with it with 1/4 turns after you figure which way is better..you will have to do this out on the water and see how it does when you first give it throttle make sure to run it a few minuets and start from a dead stop several times after each adjustment. keep all carbs the exact same. but I doubt this is what is causing your original problem. dont forget to check spark

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

I know this may scare you but you could also have some bad recirt valves in it with the bog you have. There is a test procedure in the OMC factory service manual for checking these. They can cause a bog or else a lean spit at idle.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

Thanks again for the help with this. I am going to start with bulb and look for fuel spill, check the plugs and then start checking compression and see if I can isolate the bad carb or plug. Hopefully the idle jet adjustment will just be some fine tuning after the fact.

Boobie - I think it is running rich at idle. So rich, that i have a lot of unburned fuel and incomplete combustion going on. If i smell gas in the exhaust and see fuel dripping out of exhaust that means it is not combusting in the chamber. Right?? Now I have to figure out why. I hope it is just a bad plug or float valve sticking.

Thanks again for all of the help and I will let you know what kind of progress I make.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

One more dumb question. Is the mtr running at the proper temperature at idle and not to cold? OMC did have some thermostat probs with your mtr back in that yr.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

I was under the impression the V6 looper 175 has fixed idle jets.
A leaking choke solenoid will flood the engine at idle, check the top of the solenoid for dampness,
pressurize the fuel bulb and look for fuel seeping around the red lever, they sell a rebuild kit for $15 for this reason.

Do the tests sparkie suggests regardless, you should know how to take the vital signs of your engine and rebuilding carbs is a very simple job.
It takes longer to get the buggers off the engine than to rebuild them.!
This video shows older carbs, yours are much simpler.
http://www.youtube.com/watch?v=o5cxBMDezuU&playnext=1&list=PL927682907A9BA566

If you have the plastic carbs, no need to remove the throttle body or disturb the linkages, just remove the plastic body.
The manual warns against over-tighteniong the screws that hold the plastic bowl, too tight and the bowls will warp.!

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust



this is from my 1995 ocean runner-ocean pro manual, which cover 90, 115, 150 and 175 hp 60 degree looper motors


bob

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

Boobie - That is funny question. Glad you asked. The boat has never ran hot. We ran out recently off of Jax, FL and the water temp right now is not even 50 deg. When the boat is on the trailer and mtr is on the muffs for a while, the pee stream will get warm and the temp gauge will correlate. But usually, summer or winter, the pee stream has great psi (25+) and the water temp is relatively cool. The temp gauge usually sits just inside the green area at the very cool side of the gauge. You can keep your hand on top of the engine (its warm) but never hot.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

An old rule of thumb. When the mtr is in the water and warmed up to operating temp, if you can hold your knuckles on the top of the block by the cylinder heads for more than 10 seconds it's running to cold. Not saying you have probs with your thermos, but this particular mtr did. May not hurt to take a look at them.

Re: 1997 Johnson Ocean Runner 175 - Strong Gas Odor In Exhaust

One more thing, I never have believed in temp gauges on the older mtrs. Especially the add ons. I've always used thermo-melt sticks or a temp gun to find the temp.