1987 Johnson GT150 Carb Problem

[kmaglothin]

Carb Model 25-B-M. When rebuilding the carbs I discovered one carb had damage enternally. What I believe to be the jets (Large tube in middle of carb with smaller tube inside) is cracked on both sides. Appears to be caused by attempted removal at a prior time. The carbs were rebuilt a couple of times. My questions are...What effect would this have had on the carb performance? Where do I find a replacement part? And most importantly, it is apparent that these are a chore to remove (as attested to by the cracks)...any tips on how to remove them?

 

[OBJ]

Re: 1987 Johnson GT150 Carb Problem

Hi Ranger...welcome to iboats.<br /><br />The lift tubes are NON-removable. Apparently someone thought they wuz and tried to remove them. If you notice, the tubes have calibration holes in them. The cracks could feed more gas to the engine than needed. This could lead to sluggish running and high carbon build up in the cylinders.<br /><br />What to do? You can get new carb or possibly a used one if you like to shop around. No doubt, carbs are an expensive item.<br /><br />OR....if you notice, the tubes are brass. Would take solder. I found one like this once.....an engine I bought just fer giggles.....and when I tore the carbs down for rebuild the lift tube were cracked...same thing as yours.<br /><br />I soldered the cracks up with a soldering iron. I made sure the holes in the tubes retained there exact diameters. Worked ok fer me. No problems with the engine (this was a 90hp with two carbs).<br /><br />Saved several dinero.

 

[kmaglothin]

Re: 1987 Johnson GT150 Carb Problem

Yep...that sounds about right. I looked closely and the cracks are of the hairline variety. They do not reach the metering holes. I think the soldering idea will work. Out of six total tubes only one is cracked. Thank you for the reply.

 

[kmaglothin]

Re: 1987 Johnson GT150 Carb Problem

Soldering worked just fine...interesting though... found another tube cracked. No evidence that there was an attempt to remove it. Wonder if it is a stress crack of some sort?

 

[clevecan]

Re: 1987 Johnson GT150 Carb Problem

I just rebuilt my GT150 Johnson carb's and seen one of the 3 carbs had cracks as well on them tubes your talking about.
stress cracks it looks/ I just did the cleaning and rebuild and put it back on. Am I wrong to run it this way?

 

[clevecan]

Re: 1987 Johnson GT150 Carb Problem

bump

 

[clevecan]

Re: 1987 Johnson GT150 Carb Problem

Ok went and ran the boat today, It still has a prob. I went by a friends boat shop and he looked everything over
and said he seen nothing wrong.I told him about the cracks in the one carb on the brass tubes and he said that
from what I told him and what he seen that I need to repair them or replace that carb. I rebuilt them to the core!
No dout on the rebuild,drained both gas tanks,replaced fuel lines,filters,cranks fine but was trying to run away
a high idel on me and if I were to push the key in it will haul the mail....So I remember seeing a post here showing
the tubes with the cracks but can't seem to find it.

 

[clevecan]

Re: 1987 Johnson GT150 Carb Problem

also tested the fuel pump and it's in good shape.....