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2005 Johnson 90hp 2 stroke bogging / stalling at low RPM

S

sweetd

Member
Hi All,

Looking for some troubleshooting ideas for my current outboard issue:

I have a 2005 90hp 2 stroke Johnson carbed outboard. I pre-mix the fuel and oil, and still have the original fuel / oil pump with the oil side disconnected and plugged properly.

My problem is at low RPMs, about at "no wake" speed. After running the motor for just a couple of minutes at low RPM, when I give it more throttle, it bogs down and dies. The fuel line primer bulb is empty at that point, but not flattened out (just soft). If I pump the bulb as the motor is beginning to bog down, the motor responds and throttles up. The bulb is located about 2 feet before the fuel line enters the motor cowling if that matters...

I have a Racor 10 micron fuel / H2O separator installed about 2 feet upline from the primer bulb, which has never had water showing in the clear bowl. I have a two year old fuel tank that is only 31 gallons and gets run thru fairly quickly.

My primer bulb hangs in the horizontal position when underway - can that make a difference as I believe the bulb is supposed to be primed in the vertical posistion with the arrow pointing up?

What else should I be looking for? Fuel pump starting to go?

Thanks for any advice you can provide.

Dave
 
what is your motor ldeling at after it comes out of quickstart? also check your carbs and make sure they are not running lean. (use a spray bottle of 50:1 fuel/oil) spray into your carb if motor speeds up it is lean, if it boggs down it's fat. let us know
 
coueytwo his fuel line primer bulb gets soft which indicates his fuel pump is not working correct?

can his carb adjustments do the same?
 
hand pump the fuel bulb when this happens, if the problems fixes itself it's the fuel pump, if it does not fix itself we need to know what the idel is after it comes out of quickstart. also use the spray bottle.
 
sweetd said:
Hi All,

The fuel line primer bulb is empty at that point, but not flattened out (just soft). If I pump the bulb as the motor is beginning to bog down, the motor responds and throttles up. The bulb is located about 2 feet before the fuel line enters the motor cowling if that matters...
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he is saying once he pumps the primer bulb it responds and speeds up again thats how you got me confused coueytwo

therefor this means that his fuel pump is not working correct and should replace it
 
you are correct omc_10, I missed read the write up, I have found many 60 deg motors that have had soft bulbs, but good fuel pumps. so my mind just jumped over to the next steps. thanks for making me reread the statement. I have found that if you let the motor warm up for about five mins before you idel out the motor will keep running, I have also found if you hit the choke (primer) twice before you throttle up it will run fine. but you are right. should look at the fuel pump.
 
sgtmaj83 said:
What you're describing sounds like a bad fuel pump. How does it perform at other than "no wake" speed?
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Motor runs great at all other speeds than "no wake". Never skips a beat.

The problem does "fix itself" when I squeeze the primer bulb, as long as I throttle up while squeezing the bulb. If I squeeze the bulb and do not throttle up, the problem continues after a few seconds.

I will check the idle speed after coming off of quickstart just so we have that information.

Thanks guys for the responses. I will report back with some more info as soon as I have a chance to get down to the boat this week.

Dave
 
ok sweetd sounds good
and coueytwo i had to read it twice also the first time i read it, it was a little missleading seems like you know alot about these outboards.
how old r u?
 
I've played with about five of these in the last year, they are good motors but are starting to do some very strange things.
 
UPDATE 07/09/10: 2005 Johnson 90hp 2 stroke bogging / stalling at low RPM

Took a closer look at the motor yesterday after work with a friend that knows more than I do about OBs.

First thing we did was change the water/fuel separator filter. Old one looked pretty clean, but we changed it out anyway as it was pushing 150 hours. Inspected all the fuel lines / connections and they all are new and tight.

After that we started the motor. My normal starting routine is to hold the key in for choke and turn the key - takes a few seconds for the motor to start. Did this without using the "fast start" lever on the throttle assembly. Motor started and ran for maybe 10 seconds and stalled out, but the H2O / fuel filter did not fill with fuel during that time.

Started the motor again, this time with the fast start lever engaged and it brought the motor up to about 2k RPM, which immediately drew the fuel thru the H2O / fuel filter, thru the primer bulb and into the motor.

Shut down the fast start lever and the motor idled at about 650-700 RPMs at idle at the dock. Pulled out of the slip and bumped it into forward gear - just barely in gear. RPMs dropped down to about 450-500 when in gear.

Gave it throttle and it did NOT bog down like usual - a very slight and quick hesitation occured, then it got right up on plane and ran fine. Repeated the idle / bump into gear and motor along, and then give it gas to plane several times, and it never bogged down like it has been.

So, it got us thinking - could it be an idle / RPM adjustment is needed at idle / low speed? What is this motor supposed to idle at in neutral? We were thinking maybe the bogging is due to the idle RPM being just a little low, and when I give it throttle, it "overwhelms" the motor and makes it bog? Also we were thinking that the H2O / fuel filter may have been "just clogged enough" to restrict fuel flow at low RPM? Now that the new one is on, the motor is getting just enough fuel at low RPM to not bog down, even though the idle setting may be too low?

Also, I have a lot of play in my throttle between neutral and when the cable actually revs the motor - like probably 30 degrees from neutral before the cable revs the motor. The cable run is very tight in the chase under the deck - really no room for adjustment, so the throttle is very "sticky", not smooth like it should be. Not sure if this can make a difference in fuel delivery at low RPM - just a thought.

Overall I was pretty happy that it wasn't bogging down yesterday, but I also felt like you do when you bring the car to the shop for a problem and the mechanic can't duplicate the issue while you are there. Then you go home and it happens again.

Anyway, that's what we came up with...I guess I will wait for input as to what my motor should be idling at with RPM, and make an adjustment from there if necessary. Anything else you guys can think of to check would be great.

Thanks,

Dave
 
usually it should be idleing anywhere from 800-1000rpm's any higher then isnt to good for the engine when you put it into gear more stress on the engine the more rpms's.

adjust your low speed needle on your carb and see what happens.

-bring the needle all the way in so it just touches (dont turn in any tighter you can break the needle off) count how many turns you turned it in so you know
-then back it out to 1 1/2 turns that is a good starting place to set your low speed
-or you can just start where you are but i would put it in all the way first so you knew exactly where it was before so if you need to set it back to that
 
Uh...the 60 eagle motors usually like the idle screws out 4-6 turns depending on the particular model. Also, the vapor pump or seperator could be bad. If the vapor pump isn't maintaining vacuum in the seperation chamber, it will soon fill with air and cause problems. Also check your pulse hose and limiter to the VRO.

A synchronization and linkage adjustment wouldn't hurt either. These motors are more sensitive to spark/throttle pickup timing. They're great motors, very reliable and a ton of torque!
 
omc_10 said:
ok well listen to dcramer i guess lol?
if 4-6 dont work then try 1 1/2
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This is a old post but my 2006 Johnson 90 v4 has the same issue. If have put in a 3/8 clear hose just before the primer bulb. There is air in the line after few minutes of operation but WOT no problem just when engine is back downed to ideal. Engine will stall after a few minutes. Is there any suggestions on the next test? I plan to use 6 gallon remote tank to check flow from remote tank for same problem. Any other steps that I may take?
 
At the top of the page you will find ---new posts----Post there.----Give all the details of what your motor is doing / not doing.----How it happened.---When it started.----What trouble shooting you are willing to do.
 
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