2002 Johnson J150PLSNF Carburetor rebuild? Fuel starvation?

[xavierisu]

Hello gents! Newbie here and needing some feedback to troubleshoot an older outboard before I invest $$$.

Symptoms/background:
2002 Johnson J150PLSNF
Carbs haven’t been cleaned/rebuild 5+ yrs
Evidence of gas (not much) on the bottom (inside cowling) after storing for extended time
Motor never fails to start but at times it would shut off at idle at the dock
After stopping to fish, at times, takes a few tries to start. After starting, would have to put in gear and push on throttle to keep engine from dying (would be okay thereafter)
I’ve noticed engine only runs around 5000rpm at WOT. At times, it would spike to 5500 which would run really well (significant MPH increase) and then at other times <5000rpm.
Not sure if this is related, but the past few times, false alarm of “No Oil” comes on. This happens in the morning and would be fine for the duration of the trip.

Any insight is appreciated. I’m thinking of getting the carbs rebuild first, meaning I need 6 kits correct? Also thinking about getting new fuel lines.

Thanks!

[xavierisu]

Anyone???!

[316jughead]

After the motor sets, try pumping the oil bulb to see if it is soft. Does the fuel primer bulb stay hard? Possible bad sender in the oil tank, unplug the wires from the oil tank and see if that stops the warning horn, OK to run motor with this unplugged. Is there a clear, or yellowing, plastic sleeve over a smaller black roller on the carb linkage arm that opens the carbs? Does the motor smoke a lot at idle speeds?

[ChampioNman]

Have a manual? If not get one. Perform the VRO tests. Check the throttle roller as Juggy suggests.
Are temps at or below freezing in the morning? What oil are you running. If a TC-W3 oil is being used you may want to try a semi-synthetic blend that will flow a bit easier on colder mornings. If you plan on ordering rebuild kits you may want to order new float bowls while you're at it. Operating range is 4500-5500 for your motor.

[xavierisu]

Have a manual? If not get one. Perform the VRO tests. Check the throttle roller as Juggy suggests.
Are temps at or below freezing in the morning? What oil are you running. If a TC-W3 oil is being used you may want to try a semi-synthetic blend that will flow a bit easier on colder mornings. If you plan on ordering rebuild kits you may want to order new float bowls while you're at it. Operating range is 4500-5500 for your motor.

Running XD100. It was 50 + degrees out this past Sunday. Ordered the rebuild kits along with new float bowls so we'll see if it solves the problem.

[xavierisu]

After the motor sets, try pumping the oil bulb to see if it is soft. Does the fuel primer bulb stay hard? Possible bad sender in the oil tank, unplug the wires from the oil tank and see if that stops the warning horn, OK to run motor with this unplugged. Is there a clear, or yellowing, plastic sleeve over a smaller black roller on the carb linkage arm that opens the carbs? Does the motor smoke a lot at idle speeds?

Primer stays hard. Minimal smoke (XD100) while idling. Boat is at the marina so I'll check next time I'm there regarding the carb linkage; probably next weekend when rebuild kits arrive. Will report back after rebuilding.

[ChampioNman]

Primer stays hard. Minimal smoke (XD100) while idling. Boat is at the marina so I'll check next time I'm there regarding the carb linkage; probably next weekend when rebuild kits arrive. Will report back after rebuilding.

If you are going to replace the float bowls don't forget to move the high speed orifices from the old bowls to the new ones. They live behind the float bowl drain screws and don't install the nylon washer under the needle seat.

[xavierisu]

If you are going to replace the float bowls don't forget to move the high speed orifices from the old bowls to the new ones. They live behind the float bowl drain screws and don't install the nylon washer under the needle seat.

Waiting on parts but took the carbs apart and certainly the float bowls needed to be replaced as they are slightly warped. This explains residual gas/oil leaking on the side. Ordered all 6.

Any watch outs when removing and installing the high speed orifices? Or is it just unscrew and reinstall in any manner.

And what do you mean "don't install the nylon washer under the needle seat?" Haven't gotten the kit so I'm not sure which parts comes with it.

Thanks!

[ChampioNman]

You'll see when the kits arrive. It would be nice to have an orifice tool, just be careful when you unscrew them.

[xavierisu]

You'll see when the kits arrive. It would be nice to have an orifice tool, just be careful when you unscrew them.

Got the kits, I see what you're talking about now! I was able to gentle remove the orifice with a flat side screw driver.

Question: Is it necessary to replace the rubber gasket between the throttle body and intake manifold (circled in red)? In order to replace the small side gasket of the throttle bottle on the port side (starboard not necessary), appears I have to remove the throttle body assembly. I have both starboard/port side gasket (p/n 0335403 and 0335404). Is it necessary? Tips? Torque spec from throttle body to manifold?

pic1.JPG

[316jughead]

Did you get that real OEM service manual? ChampioNman told you to get a manual.

[xavierisu]

Did you get that real OEM service manual? ChampioNman told you to get a manual.

Tried finding free literature to no avail and was hoping to get feedback from the community before purchasing (the SELOC one).

I came across a tutorial specifying 84 in lbs from throttle body to manifold. Does this sound right?

[ChampioNman]

You can down load a 1999 manual from the stickies above or try Ebay or www.outboardbooks.com. nothing much has changed between 1999 and the 2002 except for the motor covers. If you need to do the timing down the road Jughead makes a very nice ignition analyzer that works better than the factory version and it comes with instructions.

[316jughead]

Tried finding free literature to no avail and was hoping to get feedback from the community before purchasing (the SELOC one).

I came across a tutorial specifying 84 in lbs from throttle body to manifold. Does this sound right?

Hold on! The carb screws hold on the throttle body, 45 to 55 inch pounds. This is why you need to get the real manual, not the Seloc. What ever you have to pay for the OEM manual is not to much, you'll need it for more than this job. You don't need to surf the net for BS when you have factory certified techs here helping. You also have to help yourself as much as possible, it saves time and you will learn more. The guys here are mostly trying to help in spare time.

[Kellen O]

ChampioNman and 316jughead are the best—listen to them.

You don’t have to remove the throttle bodies. Remove the lower cowling and then you’ll be able to remove/rebuild one carb at a time.

Got the kits, I see what you're talking about now! I was able to gentle remove the orifice with a flat side screw driver.

Question: Is it necessary to replace the rubber gasket between the throttle body and intake manifold (circled in red)? In order to replace the small side gasket of the throttle bottle on the port side (starboard not necessary), appears I have to remove the throttle body assembly. I have both starboard/port side gasket (p/n 0335403 and 0335404). Is it necessary? Tips? Torque spec from throttle body to manifold?

pic1.JPG

[316jughead]

The OEM service manual shows how to remove the carbs, start with the top carb and replace one of the carb bolts with a shorter bolt. It even has a P/N for a bolt. but just a shorter one to keep the throttle body tight is all that is needed. There already is a bolt on the bottom of the throttle body. Then you can remove the carbs and replace them starting from the bottom carb up, makes it much easier. Most of us started doing it this way before it was in the manual.

[xavierisu]

Thank you everyone for your input, much appreciated! As a newbie, took me all day Saturday but I was able to rebuild all 6 carbs and thus far no more leakage!

Was also able to replace fuel hose and decarb with engine tuner as well. Sat it overnight, took it out Sunday afternoon and engine is now running consistently at 5500 rpm at full throttle vs topping out at 4800 previously.

Idle is still a little rough, cuts off at times. Ran out of daylight so I'll be tackling this next weekend.

Idling at 600-700rpm. Where should this be or toggle with the idle screw to fine tune it?