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1989 110HP Johnson Will Not Hold Idle

mr_johnson

Regular Contributor
What could cause this outboard

What could cause this outboard not to hold idle after I return the Fast Idle Lever to it's rest position?

Cameron
 
"The idle has to be set with t

"The idle has to be set with the boat in water, not tied up and in gear at about 800rpm.
Whatch out so the exhaust relief holes at the leg is not under water, as this might create too big a back pressure."
 
Good Point Moreton.

I am tr


Good Point Moreton.

I am trying to ensure regualr flushing whilst at home.

When u say idle needs to be set whilst boa tin water - how to do this?

Cam
 
"Launch the boat for final adj

"Launch the boat for final adjustment,
If running in barrel/muffs, You may set the initial idle unloaded at 1000 /1200 depending on back pressure."
 
What could cause this outboard

What could cause this outboard not to hold idle after I return the Fast Idle Lever to it's rest position?

Cameron
 
"Cameron,

If the engine has


"Cameron,

If the engine has good compression and will not hold an idle when adjusted properly, the problem is usually one of two things.

Either there is an ignition problem which is causing the engine to run on less that four cylinders, or there is a fuel problem such as a clogged idle jet, flooding carb, broken reed valve.

Tony"
 
"As Tony states:

Compressio


"As Tony states:

Compression... What are the readings on all cylinders?

Ignition... With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

NOTE: The 7/16" gap is important. Using spark plugs to test the spark is a waste of time.

Spark plugs should be Champion QL77JC4 plugs, gapped at .040 .

Let us know what you find."
 
"Your motor is nearly 20 years

"Your motor is nearly 20 years old! It is nothing but a 2 stage air processing " MACHINE " and at idle there is more time for leakage to occurr.The first stage is the crankcase and all its parts --------- reeds, crankshaft seal rings, oil seals, piston skirts etc.The first stage ( crankcase ) operates the same as a compressor. It then tranfers this air into the cylinder ( does not boost pressure ) it pushes the exhaust out.----- LOOK FOR INTERNAL WEAR IN YOUR MOTOR!!!!"
 
"Thanks Geru!

Gents, I have


"Thanks Geru!

Gents, I have drained all 4 carbies by removing screw in each one. 2 bowls had fule in it. The other 2 - not good - one ahd no fuel come out, the other had a small trickle.

Anyway, I primed all 4 carbies with screw out and flushed them all with fuel by priming. All back together and idle is now held very well with motor sounding much better than beofre!

Will keep looking into the other points recommended above.

Keep those good ideas coming guys.

Camern"
 
Really!!! -----You only have t

Really!!! -----You only have to remove the screw on one side to drain the carburetor.When you remove the screw on the other side the bowl is already drained!!!!!!!!!!!!!!!!!!!!!!!!
 
"The main jets are not likely

"The main jets are not likely a cause of an idle problem unless they are completely blocked.
There is only one way to properly clean them, and that is by removing them.
You may 'flush' them by removing one screw at the time, but I do not like the idea of fuel all over the place.
Go to the BRP parts catalog and get a picture of the 'internals'."
 
"Those plugs are access to the

"Those plugs are access to the main jets like Morton says.The 2 venturis share a common float bowl.It indicates that you have not had these carburetors apart for inspection/cleaning , you would have noticed this.Reading all the posts on this motor seems to indicate that you are looking for a 5 minute solution on what may be a tired / worn out motor-------just not going to happen."
 
"Cameron..... Remember to get

"Cameron..... Remember to get back to us with the compression and spark readings. Here's a spark tester you can make rather cheaply.

(Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas the!y could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:


..........X1..........X2

.................X..(grd)

..........X3..........X4

LM/MG/AB... Lighten up!"
 
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