2000 Johnson 150 WOT problems

[JoePA]

Sorry guys I don't have his model number available but I can get it in a few days when we are back up at the lake. Friend of mine has this engine and it will not go over 4500 RPM. It starts fine and gets out of the hole fine but jut won't go past that RPM. This all started after he ran out of fuel. He replaced the plugs and drained the water separator but didn't replace it, He's doing this next time he's up.

I'm going to check t make sure he s getting WOT and the butterflies are fully opened. I'm also going to make sure nothing came loose or broke. Is there anything else I should look for? He says it runs fine with no miss or hiccup.

Thanks
Joe

[ChampioNman]

Check the fuel filter and you may want to remove the carb drain plugs and make sure the high speed orifices aren't clogged up and make sure they are fully seated.

[JoePA]

Ok we did all those things and still not opening up. Max Rom is 4500. He pressed in the choke and no change and if held in the engine just starts to die. I think he's got a cylinder that's dropping out somewhere. I don't think he has a manual but I'll see what I can when I can actually put my hands on it this weekend. Any other areas to check?

[ChampioNman]

Comp check is next. If good either pack or stator.

[JoePA]

Thanks fred. That's our plans on sunday...back to the basics...comoression, fuel and spark. I'll keep you posted.

[JoePA]

Comoression checks out ok, throttle blades open fully and from what we can tell the electrical system checks out. We did find out that the hill swith doesn't work so not sure if they is what's causing issues. We pulled the plugs and this is what they look like. The port looks like they aren't during and the starbord side looks super rich.

Model J150PLSSC

[JoePA]

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[jeffbob]

I have the same motor only it's a '99 and had the same problem. I had a bad thermostat and the carb bowls were warped from alcohol in gas. My mechanic found this by having someone squeeze the primer bulb while watching the carbs for leaks as he watched his side while trimming the motor up. Both guys started to notice the carbs leaking gas. After tearing them down the put them on glass to look for warping and could not see it. The internal baffles in the bowls had bowed over causing air to be sucked in instead of gas. If you need to do this rebuild be sure to transfer the high speed jets to the new carb bowls. Good luck.

[JoePA]

Thanks Jeff! It went down to the mechanic this morning so we'll find out what the problem is/was by next week.

[JoePA]

Just an update. Ended up being a bad head gasket. Pulled the heads and the one was warped. Back up and running.

[ChampioNman]

Uh Joe, unless something has changed the 60* motors don't use head gaskets, they use O rings on each cylinder.

[JoePA]

Oh that's good to know cuz the mechanic said it was a bad gasket. I'll have to check the receipt when he picks it up. Thanks for the info

[JoePA]

So, Here we are a year later and the engine is doing the same thing. I think the mechanic that did the repairs was full of crap! Pulled the hood and noticed to of the carbs are have a horrible fuel leak and I think every bowl is warped. New rebuild kit and bowls on order. Any issue with Sierra Carb kits?

[ChampioNman]

Spring for the $4 more for the OEM kits you get the float bowl and ethanol resistant gaskets. Don't use the white nylon washer under the needle seat. Tighten until snug in an X pattern then once more around until tight just don't over tighten them.

[JoePA]

Thanks Fred! Are the parts from Iboats.com OEM stuff?

[ChampioNman]

Never ordered from Iboats Joe. I know www.boats.net and www.marineengine.com are OEM.

[omcforever]

Thanks Fred! Are the parts from Iboats.com OEM stuff?

Sometimes,,have to check. They also sell Sierra and a few other off brands. I use then sometimes,,,,

[JoePA]

Good to know. I was going to put the order in through them as they had the bowls but I'll try the others instead.

Well all the carbs are off and disassembled and every bowl is warped and 4 out of the 6 don't even touch the gasket where the emulsification tube is. I think this is where the surging problem was coming from. Going to put the order in. I'll keep you posted.

Thanks again gentlemen!

[JoePA]

UPDATE: The parts came in Friday, Bowls and carb rebuild kits. Replace all 6 bowls with rebuild kits and the engine runs perfect! Thank you everyone.

[Bassmeister]