fuel restriction need help

[semperfish13]

Hey guys, so I have a 98 Johnson 150 ocean runner. It ran great when I bought it. Then had water in fuel issue. Wouldn’t start. I drained the carbs cleaned out tank and changed the plugs and it fired right up. Took it out and had a check engine light and the engine would bog down/ surge then usually stall out but not always. It will idle fine on earmuffs all day. Soon as a load is applied cel comes on and no power. It will run good for a few minutes at most. I’m leaning towards a carb issue after replacing all fuel lines and anti siphon valve. when I drained the carbs i noticed 4/6 of the drain screws did not snug tight and are stripped out. could this cause excess air being pulled in? Tried taking it out last night and same issue. Bottom port side plug was oily the rest seemed clean/dry. When we pulled the boat out i noticed oil on the skeg. This morning i was able to do a compression test although it was on a cold engine and all 6 cylinders were at 90psi. Waiting to get the correct spark plugs tomorrow napa didnt have all 3 in stock. champion QL78YC.

 

[boobie]

Edit......

 

[GreenLakeBayliner]

I think these motors are prone to having power packs fail once they get warm or hot

if it idles just fine but only dies after it’s been run for a bit then that would be my suspicion

 

[Chris1956]

The stripped out screws are the brass hex bolts at the base of the carbs? Those are main jet covers. I think they would leak fuel if they were sufficiently stripped, but not air.

You need to make sure the main jets are clean,or you will not have any power. Check the carb bowls for warping. The plastic bowls can be purchased for $25 ea, if you look around the web.

A Check Engine alarm is fuel restriction. Check main strainer under the airbox for dirt. Did you check vapor separator for sticking? It has a needle valve and float also.

Check fuel tank vent for clog.

 

[semperfish13]

Chris1956 the regular flathead screws to drain the carbs. So it ran at 35 mph according to the gps for around 1/2 mile then it started bogging down and no power then it would not start at all. Not sure if it was just running on what i pumped into it priming it then the pump wasnt pumping anymore? Can i check the main jets without removing the carbs?

 

[jakedaawg]

I'm gonna chime in here...the fuel restriction is a must fix. Anything upstream of the vacuum switch can set it off, cheap fuel line, bad cowl connections, anti-syphon valve, bad bulb, etc. The cheap lines have an inner layer that seems to break down and such shut with out any evidence as fas as visually inspecting.

These carbs and throttle bodies can be a little tricky as far as mounting. There is a spaghetti oring to deal with and the plastic bodies and aluminum throttle bodies tend to warp and leak out the throttle shafts if not installed correctly. I believe experience and a torque wrench are a must.

 

[semperfish13]

I got the fuel pump and vro pump off. They looked clean no tears in the rubber diaphragm. I have a buddy selling all 6 carbs off his 95 Evinrude intruder 150. Would these fit? They were working fine but he blew his motor. Already replaced all the lines brp primer bulb and 2 different anti siphon valves. Put new plugs in today and it fired up first try. What could cause me to keep fouling plugs?

 

[semperfish13]

Update, got the carbs ont he starboard side off. Only had time to remove these 3 and take them apart. top and bottom 2 looked clean, middle carb ad some crap/sediment in it. The carbs i found from a buddy are the same part number so they should fit good. Gonna pick them up tomorrow and put them in then clean the other carbs i have and see what i can find. WIsh me luck!

 

[Chris1956]

The idle mixture screws are under a cover(and gasket) on the throttle bodies. I would recommend you remove the covers and clean that area with the gumout spray. No need to remove the idle mixture needles, unless that are real dirty.

 

[semperfish13]

ok sounds good, i will inspect those too. I am waiting for a carb sync tool in the mail. I will get the carbs reinstalled once i receive it and see how it goes. Its tough because it idles fine with no cel on ear muffs so the only way to really test it is on the water.