2000 Johnson 150 Issues Running

[BartJohnson]

I have a 2000 Johnson 150 two stroke that's making me want to pull my hair out. Four years ago I replaced the VRO pump. And then the boat sat for... a bit. This year I replaced the external fuel lines (it's on a Glastron runabout and I didn't know how to get at the internal fuel lines that ran under the floor at the time). I took the boat out and it ran better than it had in years... for an hour. Then I barely was able to nurse it back to the dock, wouldn't idle, stalled out as soon as I got it in gear, etc. Once I got it back I realized (try not to laugh) the gas in the boat is probably almost four years old. (had a kid, problems at work, started camping a ton because of COVID, yadda yadda, I know. I'm an idiot).

I drained all the fuel. I put in five gallons of non-eth along with a pint of seafoam, towed it around a lot to try and slosh around in the tank, and ran it through the primer bulb to a waste tank to try and clean everything out. Drained all of that, cleaned the carbs with carb cleaner (not removing them, just cleaning in place), and put fresh gas in. Again, the boat ran great, in the yard. Got to the lake and I again could barely keep it running and it was smoking blue like crazy. I'm fairly certain it's getting too much oil, but would that really cause it to barely run?

I did a compression check and I got 120, 120, 120, 120, 110, 110 (both low numbers are the lowest two cylinders).

I'm tempted to rebuild my old VRO and install it, but am I missing something here? Can a VRO pump really go bad with less than 20 hours on it?

None of the shops locally can look at it for a month.

 

[Chris1956]

Sounds like the carbs are still dirty. Firstly clean the main strainer and make sure the oring and rubber gasket are good and inplace. An air leak into the gasoline line will cause more oil to be pumped into the gasoline, which is what you are seeing.

The main jets are easy to clean. They are in the carb bowls, under the brass plugs. The sidecovers on the throttle bodies cover the idle needles. 3 of them are easy to clean with the carbs installed. The other 3 are on the inside of the carbs. The throttle bodies usually need to come off.

Give a gumout blast to the idle orifices' on each carb. They are about middle middle of the carb front.

If that don't get it, you need to pull the carbs, and possible the throttle bodies and a full cleaning. There is a screen in each carb fuel inlet. Not sure if it can get dirty, and I think you can clean it with the carbs off.

if you pull the carbs and clean 'em, replace all gaskets, inlet needles and seats. Replace floats if those look suspect at all. Check the carb bowls with a straight edge. They warp and cause all sorts of issues. Replace them if they are warped.

 

[BartJohnson]

An air leak into the gasoline line will cause more oil to be pumped into the gasoline, which is what you are seeing.

This is why you ask random people on the internet. I was in a hurry and didn't install one of the hose clamps (it broke) after pumping out all the non-eth/seafoam fuel. I'll have to see if that makes a difference and get on cleaning those carbs better.

If I do end up having to pull the carbs are there any good videos on syncing them? I have the repair manual, and I'm not fully scared of the task. I've never synced a carb though, everything I've worked on before has only had one.

 

[Chris1956]

You do not need to pull the idle mixture screws out of the throttle bodies. They have a side cover over them. Pull the cover, spray 'em down with carb cleaner and install new cover gaskets. There are no other adjustment on the carbs, except for making sure the throttle plates open at the same time.

You will want carb kits, and throttle body base gaskets. Double check the part numbers of the aftermarket carb kits. I ordered a set of kits, and they were real close to the right ones, but one of the gaskets was wrong. I ended up returning them.

I would use the OEM part numbers from crowleymarine as gospel. Cross check those against a couple of web supply places and get a consensus on aftermarket carb kits to fit your motor.