How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Tan Your Own Question
Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10618
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
25721800
Type Your Boat Question Here...
Tan is online now
A new question is answered every 9 seconds

I have a 2001 Johnson 150 that the top carb is spitting

Customer Question

Hello I have a 2001 Johnson 150 that the top carb is spitting out fuel at idle and the engine sneezes after a high rev up
Submitted: 7 months ago.
Category: Boat
Expert:  Tan replied 7 months ago.
Hello. My name is***** is signs of a bad reed valve # ***** This allows the fuel to be spit back out on the down stroke of the piston. This will also cause a lean fuel condition which causes the sneezing.You will have to remove the carb throttle body # ***** to inspect the reeds inside the intake # ***** You may have to pull the intake to inspect closer if you can't see the bad reed. http://www.marineengine.com/parts/evinrude-johnson-parts-diagrams/JOHNSON/58674.jpg Post back with questions.
Customer: replied 7 months ago.
How would I tell if reed valve is bad and if bad how do you replace it? easy job, hard job?
Expert:  Tan replied 7 months ago.
The reed will be cracked or you will see broken pieces off the reed plate. This isn't a hard job just remove the carb throttle body and the intake remove reed boax and replace reed plate. I would inspect all the reed plates. They do break over time from fatigue. Easy job! Here's an example of bro***** *****s. The damaged reeds are the ones with the holes.http://i46.tinypic.com/fdee11.jpg
Customer: replied 7 months ago.
Before I do that, what about other checks...i.e. are there any adjustment screws that would cause this? what happens is only at idle speed do I see fuel squirting up the tube in the throat of the top let carb, when I rev up the fuel stops squirting out that hole, the sneeze sound only happens after you rev high then go back down quickly
Expert:  Tan replied 7 months ago.
No adjustments will cause this. When the engine is running it is creating a vacuum in the venturi of the carb which pulls fuel up through the tube in the carb. This is normal. When you say tube and hole do you mean the same thing? If you just rebuilt the carbs there won't be a problem/ The reason the carb is spitting fuel out is the reed is allowing air to blow back through the carb. The reed is supposed to let air in not out.
Customer: replied 7 months ago.
ok, let me go check....
Expert:  Tan replied 7 months ago.
With the engine running hold a piece of paper in front of the carb does it blow away from the carb or just pull toward the carb? You don't hold the paper over the front on the carb hold it away about 1" moving the paper closer or further away. You don't want the paper to suck up against the carb. If the paper blows away from carb then you have a bad reed.
Customer: replied 7 months ago.
Just tried the paper test, paper sucked towards all carbs
Expert:  Tan replied 7 months ago.
Did the paper blow away form any of the carbs?
Customer: replied 7 months ago.
No, sucked towards all
Expert:  Tan replied 7 months ago.
When you are revving the motor and it stalls are you in the water or on a hose? Does the engine run poorly?
Customer: replied 7 months ago.
I am in the water at the dock revs ok just does a sneeze at high revs when coming back down
Expert:  Tan replied 7 months ago.
Does it do this when you run the boat up to full throttle in gear?
Customer: replied 7 months ago.
The boat does not get past 3500 rpm, it feels like it is only running on 5 out of 6 cylinders, new plugs, etc. That top carb the one with the fuel coming into jet
Seems to be flooding that cylinder
Expert:  Tan replied 7 months ago.
Didn't you just rebuild the carbs? Did you replace fuel inlet needles and seats? How did you set the float height? What do you have the idle jet set at? Have you done a compression test on all cylinders?
Customer: replied 7 months ago.
Compression is 90 on all cylinders
Customer: replied 7 months ago.
Motor is new to me, supposedly fresh rebuilt power head, but has not run since February
Customer: replied 7 months ago.
Maybe I will try switching carbs around...
Expert:  Tan replied 7 months ago.
Didn't you just rebuild the carbs? Did you replace fuel inlet needles and seats? How did you set the float height? What do you have the idle jet set at?
Expert:  Tan replied 7 months ago.
Have you checked the spark on all cylinders? When a customer tells me they just rebuilt the carbs I have to figure they have done all the checks I am asking about. So if you had just told me the engine is running poorly what is wrong we would have gone through a trouble shooting procedure. Your symptoms are all starting to look like a carb issue. So I need to know what you did for a carb rebuild? If the carb is actually flooding then the inlet needle is bad or the float is adjusted wrong. Did you replace the inlet needles?
Customer: replied 7 months ago.
I think I solved it, looks like the previous owner had a line coming from the pump attached to the top carb on an inlet, was pushing exhaust through carb pushing fuel push
Expert:  Tan replied 7 months ago.
That would sure do it. I don't know how he could of managed that but anything is possible.
Customer: replied 7 months ago.
Herr are the photos if you ever have this happen again...not sure if that tube should have been capped?
Expert:  Tan replied 7 months ago.
That is where that is supposed to go.
Customer: replied 7 months ago.
Funny it only floods when attached, when I remove it, no more flooding?
Expert:  Tan replied 7 months ago.
That attaches to the vapor pump. The vapor pump # ***** has a broken diaphram. Crankcase pressure is blowing through the pump. http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=2001&hp=150&model=E150WPLSIF&manufacturer=Evinrude&section=Fuel+Bracket+%26amp%3B+Components
Customer: replied 7 months ago.
I found out where it was supposed to go...that hose terminates into the exhaust cover, there is a hole for it.
Expert:  Tan replied 7 months ago.
Where is the hose that is supposed to go to the nipple? I can't tell from the pics you posted what's up with the hoses.
Expert:  Tan replied 7 months ago.
Sorry I have to leave for a couple of hours. Will be back if you still have an issue.
Customer: replied 7 months ago.
Ok fuel leak stopped out of carb, took it out for test run, only got to 4000 rpm max, took all the plugs out to check all looked good except one was black and oily looking
Customer: replied 7 months ago.
These were all new plugs to start with
Expert:  Tan replied 7 months ago.
That cylinder isn't firing correctly or you have to much fuel. Do you have a timing light to check spark at full throttle? It could also be a bad spark plug. Can you clean the plug and put it in a different cylinder just to verify it isn't the plug?
Customer: replied 7 months ago.
I already did that, all of the above...same results though...unfortunately I don't think you are going to be able to help me with this one Tan, but thanks for trying.
Expert:  Tan replied 7 months ago.
The only thing that will cause the plug to look like that is to much fuel or loss of spark. Was this plug in the cylinder that was flooding? Have you tried running the engine on a different fuel source or squeezing the primer bulb when you are running at full throttle?
Customer: replied 7 months ago.
This was a different cylinder, I am running off of a 6 gallon spare fuel tank with fresh non ethanol fuel, pre mixed with tcw3, bulb firm at throttle.
Replaced fouled plug and re tested...I am going to switch carbs around and then look into cdi, electrical issue
Expert:  Tan replied 7 months ago.
Ok a timing light will verify spark at full throttle just watch the flash of the timing light. The flash should be steady with no dead spots on all cylinders.
Customer: replied 7 months ago.
I wont be able to get to this tomorrow, but will on Thursday and will let you know what happens
Expert:  Tan replied 7 months ago.
Ok I will be here all day Thursday.
Customer: replied 7 months ago.
Hi Tan, well I ran the boat today, she is a 21ft center console with a 2001 johnson 150 with a 15 X 16 stainless 3 blade prop.
Starts, idles, and cruises great (3000 rpm = 23 mph GPS, 3500 rpm = 29 mph GPS) problem is she will not go past 4200 rpm, she hits 4200 with throttle maxed out and is going 36 mph (GPS), checked spark on every cylinder by pulling plugs and can see spark jumping. Ideas?
Customer: replied 7 months ago.
Also I found the sneeze issue and have fixed that, it was a vacuum line that was not attached to one carb.
Expert:  Tan replied 7 months ago.
Are you sure you are getting full throttle are the throttle plates completely open? Is the timing advancing to full advance? Finally do we know the tach is reading correctly?
Customer: replied 7 months ago.
Throttle plates are wide open (checked that) tach appears to zero out and function properly..all cruising speeds are perfect and are in the good range for speed...not sure about the timing advance though??
Expert:  Tan replied 7 months ago.
Check the advance at full throttle. If it is off then you will have to take it to a dealer to have the timing set. Setting timeing requires a special tool. They don't have to run the boat to set the timing.
Customer: replied 7 months ago.
I think the timing is set correctly, one other thing is the #6 spark plug is black where the others are normal, so my thought is #6 might have something going on with the old vro pump that was disconnected or maybe something else?
Expert:  Tan replied 7 months ago.
Have you checked the fire on that cylinder at full throttle? Being the bottom cylinder you could have a bad crank seal not allowing the cylinder to fire correctly getting air in and not enough fuel. When you are running the boat with the cover off the carbs put you hand over each carb see if it will pick up rpms. You don't have to completely cover the carb just partially. Also with a timing light shine the light into each carb. Do you see the fuel flowing the same on all cylinders. Do these tests at full throttle.
Customer: replied 7 months ago.
Will do tomorrow and report back...
Expert:  Tan replied 7 months ago.
Ok.
Customer: replied 7 months ago.
Does this motor have a high speed jet or high speed adjustment anywhere? when I rebuilt the carbs I did not see any?
Expert:  Tan replied 7 months ago.
Yes it has a high speed jet # ***** it is in the very bottom of the carburetor behind the drain plug # ***** If it is clogged the engine will not fire on that cylinder. http://www.marineengine.com/parts/evinrude-johnson-parts-diagrams/JOHNSON/58651.jpg
Customer: replied 7 months ago.
That is something I need to check then, I do not remember seeing it??
Expert:  Tan replied 7 months ago.
Absolutely. It takes a very small flat blade screw driver to r&r the jet.
Customer: replied 7 months ago.
Will do tomorrow and report back...thank you
Expert:  Tan replied 7 months ago.
OK
Customer: replied 7 months ago.
Hi Tan, so I removed, checked and cleaned every high speed jet, then water tested again, same exact result..
Starts, idles, and cruises great (3000 rpm = 23 mph GPS, 3500 rpm = 29 mph GPS) problem is she will not go past 4200 rpm, she hits 4200 with throttle maxed out and is going 36 mph (GPS)
I then checked the timing advance on the flywheel, played around a little but made no difference.
Expert:  Tan replied 7 months ago.
Can you get a vacuum gauge and tee it in to the fuel supply line. Run the boat what does the gauge read? Did you try covering the carbs when you ran the boat? Did you shine the timing light into each carb and check fuel flow?
Customer: replied 7 months ago.
Will try that and let you know..
Expert:  Tan replied 7 months ago.
Ok try swapping the carbs around see if # ***** changes any. This will at least eliminate the carbs.
Customer: replied 6 months ago.
Hi Tan, well got to do more testing in water...
Same results..to summarize what was done so far:
Checked compression, all good (90 + on all), within 10 % of each other
Rebuilt all 6 carbs, adjusted float bowls on all
Checked all for spark (put boat in water, in gear, pulled one plug at a time to hear the drop and see the spark jump)
Changed out props from 15 X 16 stainless to 14 3/4 X 17
Ran off of spare tank with fresh rec 90 fuel (all pre mix, no vro connected)
Checked and adjusted timing +/- to see if any difference...none
Ran offshore with cover off looking at carbs, plenty of fuel spraying, fuel bulb perfectFixed and attached all vacuum hose (that what was causing sneeze after rev in beginning)
Boat hull is 21 ft Logic, not holding water, dry and light
Checked all spark plugs after running, look same
Decarbed motor with seafoam in fuel and also through carbsBoat will not go over 4000 rpm trimmed, max speed 35 mph"Feels" like it is not getting full power...

Related Boat Questions