2000 johnson 150 fuel issue

Jimidude87

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Mar 16, 2018
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Hello everyone new to the forum here...i have a 2000 johnson 150 that is fairly new to me. A little backstory, i got the boat about 3 months ago. The previous owner had it sitting for a while. I put new plugs, fluids, cleaned the carbs, did a decarb etc.

The first couple times i took it out it ran really good. I would get a fuel restriction alarm at about 4k rpms but it's running off a portable tank right now so i figured this was why. The last time i took it out it was running normal. I had it at wot and was only getting about 4000-4200 rpms. The fuel alarm went off and when i looked back the primer bulb was sucked flat. I shut it down for a bit reprimed and seemed to be good. I got it going again and when it got to 4k it started surging bad...like from 4k down to about 2k and then back. It did this for a couple cycles and then died. Couldn't get it started again. I've checked the spark and that's fine.

The only other thing i could think would be the fuel pump. I plan on replacing it but don't want to drop a couple hundred dollars if i don't need to. Does this sound like the vro? Another thing which concerned me was when i was trying to start it and while it was running there seemed to be quite a bit of fuel/oil in the water. I'm really hoping it's just something simple and not something that I'm going to need a new motor 😵

Another thing to mention would be the fuel lines from the portable tank are new and the primer bulb is new.

Thanks in advance for all the help!
 

jbuote

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Aug 17, 2016
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Hey there!! :welcome:

Not a pro, but you said the primer bulb went flat...
Off the top of my head, that says there's a restriction between the primer bulb and the tank..
Could be a vent not open, clogged screen in tank pickup tube etc...

Is the tank clean, pickup tube in it clear and no obstructions? Tank vent open?

Wouldn't suspect fuel pump yet.. The fact it went flat says pump is working, but sucked all the fuel out with nothing to replace it thus flattening the primer bulb..

Just my newbie $.02
 

Chris1956

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Mar 25, 2004
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Jboute is right on the money. Fuel pump is likely working.

Since you are using a portable tank, perhaps the vent is not working, the fuel screen on the pickup is partially clogged, or the fuel line is too small. It is also possibe the primer bulb has a clog at the upstream check valve.

Your motor is best with a 3/8" ID fuel line.

You might take a compression test to rule out any engine damage.
 

Jimidude87

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Mar 16, 2018
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When the problem started i tried opening the fuel cap but it didn't help. I just got the correct tank and will be installing hopefully sometime this week with the correct fuel lines. I was thinking a primer bulb problem also but put a new one on and no change. I visually looked at the fuel pick up line and it didn't appear to have any obstructions. I even tried running a new piece of fuel line in the tank but had no luck. The reason i thought fuel pump was because after it died it wouldn't start again and was trying to turn over but didn't seem to be getting fuel. If i would pump the bulb i could get it to start after a while but it would die almost immediately.

I'm by no means a marine mechanic but am somewhat mechanically inclined. I did a compression test when i first got it and all cylinders were at 65...but that was before decarbing and running ring free through it (which i was gulf by a marine mechanic could raise the compression up to 20psi if it was gummed up and sat for a while which it did). The only thing that confused me was the first 2 times i took it out it ran great and then the third time it was like a switch flipped and it gave me this problem.
 

jbuote

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I did a compression test when i first got it and all cylinders were at 65...but that was before decarbing and running ring free through it (which i was gulf by a marine mechanic could raise the compression up to 20psi if it was gummed up and sat for a while which it did). The only thing that confused me was the first 2 times i took it out it ran great and then the third time it was like a switch flipped and it gave me this problem.

Ok..

I'll echo the need for another compression test..
65 is low like you said.. The decarb, even if it brought it up 20psi, still only gets you to 85...
Still quite low.. At least I think it is.. (maybe not that low for 2000?)

Then, third trip out, switch flipped and you have a problem..

Do another compression test now..

Again, purely a newbie here, but based on what you said there, I'm starting to think this engine MIGHT have more issues, but let's go one step at a time here to nail it down and/or eliminate issues like Chris1956 said.....

Start with that compression test and let's see what happens..
I'll help as much as I can, but will certainly defer to the seasoned folks here without hesitation! lol
 

Jimidude87

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So I have an update. I went out and did another compression test and the results were the same...all cylinders at 65...i tried to start it just to see what would happen and here's what did...

When i turned the key it would crank but not start. I tried to throttle up in neutral to see if that would help and it fired up, ran for about 5 seconds and died. I tried again and it would fire up but die almost immediately. I took the cover and air silencer off and visually everything looks good. I put a new piece of fuel line in with a new primer bulb to eliminate that problem. I tried messing with the red thing between the carbs (sorry have no idea what it's called but i believe it's the choke) playing with this i could get it to start for maybe 5 or so seconds but it would not stay running.

I'm fairly certain it's not a spark issue or it wouldn't fire up. I think it's a fuel delivery problem because when it dies it just acts like it's not getting fuel. If it were the carbs that went bad would they all 6 go at the same time? I feel like if that were the problem maybe 1 or 2 would go and it would run crappy but still run. This is what leads me to believe it's the fuel pump.

I almost feel like i could go bang my head on the motor and get the same progress as I've gotten.lol
 

clanton

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Jul 9, 2001
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4,876
If using the VRO system, when the fuel lines are restricted, will pump lots of extry oil. You should have lots of smoke and oily plugs. Pump and lines should be checked. fuel pressure 3 lbs at idle. Engine should have about 115 psi.compression. Important to have oil 50-1 in tank while working on pump.
 

Jimidude87

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Mar 16, 2018
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the water pump was replaced right before i got it. I believe it's still good because when the motor is running it's peeing out of the back and I've never gotten an overheat alarm.
 

Jimidude87

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Mar 16, 2018
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Ok guys i bought a new spark tester and a new compression tester. I have good spark on all cylinders and the compression test was as follows: 90,92,90,90,88, and 90.

I bought a new ignition switch today but it was the wrong one so i couldn't try that.

I can hear the primer solenoid clicking but it's weird. It doesn't click when i push the key in but after trying to start it when i let off the key i can hear a click from it a few seconds later.

Another thing i noticed tonight is there is a nice stream of black in the grass behindthe exhaust. I'm assuming this is from the exhaust. Could it be that it was just still really gummed up and from running it a few times all that gunk has made its way through the fuel system and this is my issue?

I got a quote today to have the carbs rebuilt and it was about $650. I thought that was high seeing how the rebuild kits are about 20-30 per carb. I think that's my next step and then if that doesn't work i think it's on to the fuel pump...

Does this sound about right?
 

oldboat1

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I'm not sure I understand what you are running in the way of fuel pump and tank. If premixing with a portable tank, you need a 50:1 mix, block off the VRO oil line at the motor, and disconnect the VRO harness. See Clanton's post #7.

Quote on rebuilding carbs is about right.
 

Jimidude87

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Mar 16, 2018
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So just to clarify. The vro is still connected and supplying oil. Right now i have a portable tank hooked up and the line from that is going into where the normal fuel line would go into the vro. The previous owner took the on board fuel tank out because the lines went bad. I just got the regular tank and am prepping it to put it back in.
 

oldboat1

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Maybe you will see improvement with the original tank (has to be clean). I would avoid any additives -- stabil, maybe. Start with what you will burn in a few runs.
 

Jimidude87

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Only problem with that is it wont start and stay running...it will fire up but dies almost immediately. And the throttle has to be half forward and the red primer lever has to be in just the right spot. It's like a dang ritual just to get this thing to start fora few seconds....
 

racerone

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Dec 28, 2013
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Stop with the " crank and hope " work.------There are issues with they electric primer or your starting procedure.-----Fuel also puts oil into the motor.-----You are risking damage in trying to run a motor with blocked carburetors !
 

flyingscott

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Do you have the arrow on the primer ball pointing towards the motor? The primer only works when the key is in the on position. If you are pressing the key in when it is in the off position, it will not work until the key goes to on. The red lever on the primer is to switch between manual and electric operation. If you are leaving the red lever on you are flooding the motor.
 

Chris1956

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Mar 25, 2004
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The gasoline for that motor would normally flow into the main strainer, then to the vapor separator, and gravity feed to the OMS pump. Is that the way you have it routed? If the fuel line is connected directly to the OMS pump, you may have it plumbed backwards.
 

jakedaawg

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I think you need to stop and regroup on this one...

1. Verify that the red lever on primer solenoid is inline with body of solenoid.

2. Verify that the fuel line is 3/8" id and the arrow on bulb points to the motor.

3. Verify that when squeezing the bulb it firms up. After it firms up continue squeezing gently and note whether or not bulb continues to depress.

4. Explain in detail your cold start procedure.

5. Take a fuel sample from motor end of fuel line into a clear bar.

report back on these findings and we will give you next steps. ...

nothing says carb job needed yet but I charge more than that to do carbs and throttle bodies with a synch and link. ..
 

Jimidude87

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Mar 16, 2018
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I think you need to stop and regroup on this one...

1. Verify that the red lever on primer solenoid is inline with body of solenoid.

2. Verify that the fuel line is 3/8" id and the arrow on bulb points to the motor.

3. Verify that when squeezing the bulb it firms up. After it firms up continue squeezing gently and note whether or not bulb continues to depress.

4. Explain in detail your cold start procedure.

5. Take a fuel sample from motor end of fuel line into a clear bar.

report back on these findings and we will give you next steps. ...

nothing says carb job needed yet but I charge more than that to do carbs and throttle bodies with a synch and link. ..

1. The red lever is in the down position towards the motor.

2. The fuel lines are all 3/8 and the arrow on the bulb points toward the motor.

3. When i squeeze the bulb it does get firm. After its firm it gets hard enough i can't squeeze it anymore unless i really crank down on it (which i haven't done).

4. My cold start procedure is as follows...pump the primer bulb turn the key to on push key in wait a few seconds and then turn the key to start.

5. I took a fuel sample from the motor and it seems fine.

All of the fuel lines are routed the same way they originally were. When i changed the lines i did them 1 at a time so i didn't screw anything up.lol
 
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