1997 Johnson 225 Idle screw and vacuum leak

[festerized]

1997 Johnson 225 Idle screw and vacuum leak
Motor: SJ225TXEUD
Idle screw adjustments on starboard top cylinder makes no change to rpm’s, if I turn two turns out and with 0 turns after a few minutes she stalls. Why it takes so long to change rpm’s is baffling, all other cylinders have a instant change to rpm’s.
Motor starts right up, motor surges after 3,000 rpm’s while in gear.
This all started after my primer ball wouldn’t get hard this spring.
I replaced fuel line from tank to fuel separator and added anti stiffen valve, for some reason my tank didn’t have it. I have a new water separator just haven’t installed it yet and don’t feel I need to.
Replaced fuel lines from water separator to deck nipple and replaced deck nipple, only fuel line I did not replace is one going thru 3” motor hose to VRO pump which I will do soon.
I eliminated the fuel system with the exception of the gas line going they the 3” motor hose by running the motor off a 2 gallon external tank.

This is what I have troubleshooted and done so far;
New fuel lines
Ran motor off external tank
Idle mixture screw 5 turns out
All carbs rebuilt
New throttle body gaskets
Switched top carbs to verify it wasn’t carb
Compression test 106 each cylinder
Replaced vacuum line on top cylinder from back of head to throttle body and checked nipples for air leaks. Apparently this is not a cross over vacuum motor as each vacuum line from back of cylinder matches each carb.
Sprayed carb cleaner backside of carbs, no rpm change
If I push in key (choke) motor stalls
Replaced three fuel lines from fuel rail to carbs, waiting on more fuel line to replace remaining.
I will remove and vacuum tested fuel rail this week.
Fuel lines were old and my thought was maybe I loosened when pulling carbs which is sucking in air. Spraying carb cleaner on fuel lines won’t change rpm’s and I don’t know any other way of testing other than just replacing.

Could it be reed valves? No gas is spitting but there is a slight dampness and sometimes a puddle on two middle carbs
Lower unit clutch dog? I watched a few vids on bad clutch dogs, similar but not exactly the same.
Maybe fuel rail cracked and fuel lines are old?

I am stumped
I did not check electrical yet, I’ll attack that next week, I’m stuck on that top carb mixture screw is the problem.
I have a vid of motor running, will try to post

 

[racerone]

Carburetors on the port side feed the cylinders on the starboard side.-----It does crossover !

 

[festerized]

Then it must have been switched when top end was rebuilt a few years ago? i traced each line to each matching cylinder. what is the correct vacuum line layout?

 

[festerized]

i posted vid on YouTube
https://youtu.be/RlCF_btkfgo

 

[racerone]

You call them " vacuum lines " in post # 1-----But are you sure you know what these wee hoses do on this motor ?

 

[festerized]

I assume positive crankcase ventilation

 

[racerone]

But your motor has 6 separate crankcases that are sealed.------They are sealed so that when piston comes down in the cylinder there is compression in the crankcase.-----The 6 crankcases are NOT VENTED !

 

[jakedaawg]

Instead of berating someone cause they called the hoses vacuum lines why dont you just explain it...at least the guy is trying...everyone already knows you know everything, try being helpful.

 

[racerone]

I am trying to make the poster think / read up on how things work one little step at a time.---------Sometimes that can be difficult to do.-----So no more input on this one.

 

[festerized]

I don’t need to “make me think how it works” If you read my post I think I did a good job at troubleshooting the issue, I spoke to 3 mechanics, all said I did a good job so far, each mechanic said they all would have done the same test. One Mech even asked if wanted a job lol.

 

[racerone]

Sorry----But post #1 says ----" apparently this is not a crossover vacuum motor "----So that tells me something !!

 

[daselbee]

On the stbd side of each throttle body, there are plates held on by 4 small screws. One for each cylinder, so there are three on stbd throttle body, and three on port throttle body. These plates cover the calibration pocket, which is simply the name for the area where IDLE FUEL IS INTRODUCED INTO THE VENTURI. I all CAPS that because that is an important point!!!!
The idle screw you are speaking of allows fuel to flow thru to this calibration pocket.
So, two things.....Either the tiny tiny holes behind that plate are clogged, resulting in no effect when you adjust screw, or the idle fuel pickup tube that extends down into the fuel bowl is clogged at the top of the tube, again not allowing idle fuel to make it thru the idle circuits of the carb/throttle body assembly.

I use welding tip cleaner wires to clear out those holes. I also suck on the idle fuel pickup tube to check for air flow. You can feel the air on your tongue very easily.

 

[daselbee]

On to the "vacuum lines".
Not vacuum lines. They are hoses used in the recirculation system, or the system designed to draw excess fuel/oil out of each intake, and more importantly, they "balance" out the intake pulses in the hopes of improving the idle.
I dont think they do CRAP!!!
Anyway, the hoses are cross connected, in that Cyl1 hose goes to Cyl2, and Cyl2 goes to Cyl1. Same for the other four cylinders in the motor.

You say..but but but they aren't crossed!!!!! Yes they are. Look carefully at the intake. The carb that is highest in the stack is the one that feeds Cyl 1. Cyl 1 is the highest cyl in the block. Note the height difference!!!! Important!!!!
So the highest carb on the intake is on the port side, and the highest cyl is on the stbd side of the block.
There is the crossover. Follow the hoses and you see that they indeed crossfeed, and that the intake is designed with the runners crossing over also.

EDIT: DO NOT get this crossover of the intake confused with the term "crossflow". It is not the same at all.

 

[Joe Reeves]

Festerized.... In reading post #1, I gather that originally the engine ran fine until one day the fuel primer bulb wouldn't get hard after which I assume you replaced the fuel primer bulb... and it was after that where you encountered a surging effect of the engine at 3000 rpm.

Is that the gist of it?

Does the fuel primer bulb now get hard when you pump it for priming?

Give us a update as to exactly what is that engine doing or not doing and try to keep it as simple as possible.

If those hoses in question that are in the process of causing a heated debate have one end connected to check valves at one point, they're most likely fuel re-circulation hoses... however I retired in 1991 so I may be in error, and if so I'm sure another more knowledgeable member will hopefully advise us of that.

 

[festerized]

On the stbd side of each throttle body, there are plates held on by 4 small screws. One for each cylinder, so there are three on stbd throttle body, and three on port throttle body. These plates cover the calibration pocket, which is simply the name for the area where IDLE FUEL IS INTRODUCED INTO THE VENTURI. I all CAPS that because that is an important point!!!!
The idle screw you are speaking of allows fuel to flow thru to this calibration pocket.
So, two things.....Either the tiny tiny holes behind that plate are clogged, resulting in no effect when you adjust screw, or the idle fuel pickup tube that extends down into the fuel bowl is clogged at the top of the tube, again not allowing idle fuel to make it thru the idle circuits of the carb/throttle body assembly.

I use welding tip cleaner wires to clear out those holes. I also suck on the idle fuel pickup tube to check for air flow. You can feel the air on your tongue very easily.

i will pull carbs and double check i cleaned them properly, and check float level

 

[festerized]

Festerized.... In reading post #1, I gather that originally the engine ran fine until one day the fuel primer bulb wouldn't get hard after which I assume you replaced the fuel primer bulb... and it was after that where you encountered a surging effect of the engine at 3000 rpm.

Is that the gist of it?

Does the fuel primer bulb now get hard when you pump it for priming?

Give us a update as to exactly what is that engine doing or not doing and try to keep it as simple as possible.

If those hoses in question that are in the process of causing a heated debate have one end connected to check valves at one point, they're most likely fuel re-circulation hoses... however I retired in 1991 so I may be in error, and if so I'm sure another more knowledgeable member will hopefully advise us of that.

Took boat for a spin this afternoon, bulb isn't as hard as it should could be, while in gear i pumped ball and rpm's rose up slightly, im pulling carbs and starting over

 

[Joe Reeves]

Just FYI.... The fuel primer bulb should become hard ONLY when pumped up to prime. When the engine is running, fuel simply flows thru it and drops to the halfway level mark. This is normal and no cause for alarm.

 

[festerized]

Question
White washer is installed on seat? My carbs didn't have this washer installed, carbs were rebuilt in 2013 and has ran fine without them.

 

[Joe Reeves]

If, where the brass float needle valve seat sits... there is a slight raised portion that resembles the shape of a washer, that's exactly what it is and does not require an additional washer.

 

[FreeBeeTony]

If, where the brass float needle valve seat sits... there is a slight raised portion that resembles the shape of a washer, that's exactly what it is and does not require an additional washer.

I learned that same lesson just recently!