Johnson 115 wont rev

[NathanG88]

Howdy all
got a v4 115 johnson was ment to be a 1992 but im unsure of the year as theres no id tags on it looks to be more like a 84ish modle.
im having problems with it in gear it wouldnt rev past 2200rpm so i replaced all the coils as one was found to be faulty didnt fix the problem now it sits at 2200rpm then will jump to 3000 but wont go higher.
iv check'd compression it has 125 psi on all 4 cylnders.
have had the carbys out and there all clean.
im at a loss as to wat would be causeing it.
looking for suggestions before i start replacing everything.

Checked my stators resistance
Left Bank
tan/white - green 34.3
Tan/white - blue 34.1
green - blue 68.4
Right Bank
Tan/white - green 33.4
Tan/white - blue 36.8
green - blue 69.3

 

[racerone]

Post pictures.---A recent purchase ?-----Two " no money spent " things to do.------Run with timing light hooked up , one cylinder at a time.----Observe how spark behaves.-----Use a strong flashlight and look into each carburetor at full throttle ( on the lake ) and observe fuel coming up the main nozzle.

 

[NathanG88]

Post pictures.---A recent purchase ?-----Two " no money spent " things to do.------Run with timing light hooked up , one cylinder at a time.----Observe how spark behaves.-----Use a strong flashlight and look into each carburetor at full throttle ( on the lake ) and observe fuel coming up the main nozzle.

I Bought it second hand as a running motor
replaced coils and fuel pump
havent rebuilt the carbys yet as still waiting on parts to arrive ( live in australia parts comming from US )

 

[racerone]

Will the seller help you with this thing ?-----A reputable shop ?-----Choke tells me it is a 1979 or older.---Looks like an 87 / 88 / 89 cowling.------Lower cowling is 1989 or newer.-----Stop running this motor until you find the issue!---Does spark jump a gap of at least 3/8" ( 1 cm ) on all 4 leads , yes or no ?------Plugged carburetor jet can starve one cylinder of oil !----Did you have the high speed jet , found in the very bottom of carburetor bowl out for cleaning ?----Checked reed valves ?-----And it could be as simple as a bad plug wire and spark jumping to the cowling.---Yes I know the cowling is plastic !

 

[racerone]

Check flywheel key too as it controls the timing.-----And no you can not find a sheared key with a timing light !

 

[NathanG88]

Will the seller help you with this thing ?-----A reputable shop ?-----Choke tells me it is a 1979 or older.---Looks like an 87 / 88 / 89 cowling.------Lower cowling is 1989 or newer.-----Stop running this motor until you find the issue!---Does spark jump a gap of at least 3/8" ( 1 cm ) on all 4 leads , yes or no ?------Plugged carburetor jet can starve one cylinder of oil !----Did you have the high speed jet , found in the very bottom of carburetor bowl out for cleaning ?----Checked reed valves ?-----And it could be as simple as a bad plug wire and spark jumping to the cowling.---Yes I know the cowling is plastic !

bought the motor private in 2020 was running fine on his boat.
iv only had it out once spent rest of time trying to fix
spark jumps 7/16 easy nice blue spark.
it has all new plug wires got them with the coils old ones were shot.
havent had the jets out just carbys off and sprayed carby cleaner thru all the jets i could see.
will pull carbys off again tommorow and reclean them all then reassemble when carby kit arrives.

 

[racerone]

Mixing gas and oil at 50:1 ?-----Replaced the water pump impeller?-----Post all the information you can so I stop asking the dumb questions here.

 

[hgxsilver]

What is the high temp idle speed? Could cylinders be grounded due to a sensor failure?

 

[NathanG88]

Mixing gas and oil at 50:1 ?-----Replaced the water pump impeller?-----Post all the information you can so I stop asking the dumb questions here.

vro has been disconected runs premix 50:1
impeller was replaced month before i bought it.
questions arent dumb working on outboards is new to me.
when i had it out today and i got it to run at 3000rpm full throttal it would rev up the straight back down to 3000.

 

[NathanG88]

What is the high temp idle speed? Could cylinders be grounded due to a sensor failure?

how would i find out the high temp idle?
when its warmd up it idles at 900rpm ?

 

[racerone]

See post #2 -----Not a good idea doing that sort of testing ???

 

[racerone]

Fact.----Your motor to me is an elegantly simple machine.----It really is 4 separate engines with a common crankshaft and block.----It is a 2 stage air processing machine.-----It needs 4 things to run properly.---( 1 ) Fuel /air mixture.----That is pulled through one carburetor bore into each separate crankcase.-----( 2 ) It is compressed in the crankcase and transferred to the cylinder.----(3 ) It is compressed in the cylinder.----( 4 ) it is ignited by the sparkplug.-----The trouble shooting should take no more than 20 minutes.-----But I can not see , hear or feel your motor.----It is 10,000 miles away !!

 

[NathanG88]

I pulled carbs off today can only find 3 jets that a removable in them. bottom carb was clean as. top carb was filthy hoping that was the problem its soaking in carby cleaner atm.
but non the of the jets or cavitys were blocked thinking maybe somthing was floating around in the carby bowl.
this is the bottom carb.

edit. just relaised my carby has 2 differnt idle jets one for right and one for left and there differnt sizes. iv already removed them. my manuel didnt state they was differnt sizes . now i dont know wich is wich.

 

[Faztbullet]

Those are wrong carbs for a 115hp. Those are 1" carbs are off a 85hp or 150hp like I have on my toon.

 

[racerone]

See post #4.----The decals say 115 HP but who knows if it is.-----Is there a disc on the block with a model / serial number ?----Same serial # as the plate on transom bracket?----Have you found the high speed jets in the carburetor bowls ?----What # are they?

 

[NathanG88]

there is a disc but no transome plate. so apart from the no on the disc i have no idea wat it is.
no jets in the bowls themselfs there all on the carb just 2 screws one either side. of the bowl with nothing in them but i will go double check and take a photo

 

[racerone]

Perhaps you are working on your first motor ??----You need to listen !------The high speed jets ( orifice plugs ) are in the carburetor bowls.----Look for them . find them and post the number on them !

 

[NathanG88]

yes this is my first outboard.
i found the orifice plugs / high speed jets i cant get them out dont have a screwdriver that will fit down the hole.
are all the orififace plugs/jets ment to have numbers on them none i have pulled out so far have had any markings on them that i could see im going to shed now to check the ones i have out.

 

[Crosbyman]

deleted

 

[racerone]

The jets typically have a number on them.----Good luck with this motor as you may need it !!