150 faststrike puff out carb

I have a j150gleom that is puffing blue smoke out of one carb sporadically at idle. I was doing a tune-up due to a miss at idle and found it. Is this a bad reed valve or just need carb adjustment. Any help would be greatly appreciated thanks

1995 150hp Johnson....... Smoke puffing out the carburetor would normally be due to a faulty leaf valve on a reed plate. However, you mention a problem being a miss at idle whereas the smoke puffing could be a strange effect of a lean running carburetor.

Before digging into it, removing the intake manifold etc..... have the engine running at idle with this problem occurring. Then stick two fingers into the carburetor throat, acting as a manual choke to cause the fuel flow to flow slightly richer. If this bit of troubleshooting smooths the idle out and causes the puffing to stop... the carburetor would need looking at.

Make sure its in barrel or lake as these have to have backpressure or chance of lean spit increases.

Messed with the motor again today tried putting fingers in carb it accumulated a lot of gas which ran out of the carburetor took video will post soon as I figure out how to do post it

Dgold, hi, the link won't work for me. Question: When did this problem start? After a storage period, or after running out of fuel? Using ethanol?

Has always had what I assumed to be a Miss since I bought the boat seems to do it after you bring the RPMs up and drop them back down do not run ethanol to my knowledge i buy ethanol free gas while running it yesterday it seems to be less frequent but always has been real random took a month to get the boat when I bought it because it was at the Marine shop being checked out

First of all thanks for the help and suggestions on this issue. I think i found the problem 1st never assume someone else did the job they were paid to do. After a lot of time and money i found that two idle screws were run all the way in. Now just hoping there is no other damage done. So i guess i will do the very thing i did not want and try to set the carbs to make the engine run right. I would take it to a marine shop but they are the only one in the area and are most like the ones that did or should of caught the problem.

These are a pretty basic carb and besides that, just ask the techs here and they will do their very best to help. I am pretty sure you found the problem alright. Start simple and work till you find a solution, good MO. Looking back at Joe's test......had this been effectively performed, you would have found the problem......."but folks, don't try this at home". Kinda spooky sticking your fingers in a running motor. Good job, Dgold.

Would of never of had a problem if payed pro would of done job right in the first place. I dislike messing with carbs because i have never had any luck making adjustments on them and now there are 6 of them to tune.but thanks to all that helped. Is there any good reason for setting idle screws all the way in on two carbs and whats the chance i did damage to the rest of the motor by running at idle while trying to find problem?

timguy said:

These are a pretty basic carb and besides that, just ask the techs here and they will do their very best to help. I am pretty sure you found the problem alright. Start simple and work till you find a solution, good MO. Looking back at Joe's test......had this been effectively performed, you would have found the problem......."but folks, don't try this at home". Kinda spooky sticking your fingers in a running motor. Good job, Dgold.

Click to expand...

A most common test that presents no danger.... no moving parts at that location.

Dgold said:

....After a lot of time and money i found that two idle screws were run all the way in.....

Click to expand...

I don't have a manual for your motor. I did some searching and it sounds like 6 turns out from lightly seated is a typical starting point for low speed screw adjustment.

You cannot adjust these carbs on a hose...engine has to be in water, level , in gear, untethered to adjust., and 5.5 turns out is starting point.

Pappy is concerned that backpressure will effect low speed mixture. You will notice a "richer" low speed while in the water. To my knowledge there hasn't been any accurate corrections on needle position to compensate for in or out of the water on this motor. For my thinking another consideration is whether the motor cowling is on or off. So to put these two ideas together, the motor will run leaner while adjusting while on the garden hose AND with cowling off. On the water with cowling in place, you will most certainly notice a richer llow speed mixture. 1/2 turn in, on the needles may be an effective compensation. Of course there is no way to make the low speed mixture adjustment with the cowling in place. For the benefit of the motors longevity, you of course want to err slightly rich than lean.

Joe, I'm just saying that this technique is great, but some readers here might get nervous. Your advice is "right on target".

Not concerned ...it how manufacturer states it should be done. Has a lot to do with block design