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Old 115hp johnson no top end.

G

Guyph_01

Contributing Member
Hi guys,

First of all Merry Christmas to you all.
Ive bought 15ft speed boat and she has this old Johnson on it. Its been sitting for a while. It started and runs fine on the hose but in the water it was a pain to start abd felt like it had only half the power a 115 should have.

Anyway so i bought two new carb kits and installed new plugs and went for anothe test and it was pretty much the same. Starts great on the hose, pain to start in the water and lacks power:(

Looking at it from the back both left cyl have about 120psi and 130psi one the right.

Details:
Model No 115693G
Serial No A312078



Any ideas on what could cause this? Is there any adjustments i need to do on the side of the motor etc?

Thankyou;)
 
Check for spark on all leads.----Must jump a gap of near 1/2" to be called " good spark ".-----They sound good on a hose , running on 2 cylinders !!----Did you remove the high speed jets from the carburetor bowls to make sure they were clean ?
 
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Prop pitch??? Remove the engine cover and run it at full throttle for a while....use hand held infrared temperature gauge to make sure all cylinders are running at the same temperature and contributing equally. These temperature gauges are available for under $25.00 on amazon and are extremely useful for diagnosing a variety of problems. if you can't get a hold of one of these, you can get a rough idea of whether all cylinders are firing by shutting it down and then using your hand to roughly compare cylinder head temperatures.
 
Racerone
While idleing ive remove each lead one by one and engine sound changed. Ill try to check the spark jump next and report back;)

Bobbyc
Nothing stampes on the prop.. no idea of pitch. Ok ill try to check the temps of each cyl;)

Boobie
How do i perform a cyl drop test? I need to buy some extra gear right?

Also
Are the comp values ok-ish?

Thx guys for the help. If anyone has any ideas of what to check/look for plz let me know;)

Guy
 
You have removed each lead with motor running, that is the drop test.----Did you remove high speed jets , yes or no ?
 
On a drop test you should notice a drop in rpm when you pull a plug lead if the cylinder is good. No drop you have a problem in that cylinder. All you need to do it is an insulated pliers.
 
racerone
Are the high speed jets the ones behind that little screw on the side of the carb? Ive remove only the needle and seat and replaced those ali plug things(not sure what they are called) and the gaskets. So no I didnt.

Bobbie
The tacho isnt working on the boat, not sure why.. How can i test it if thats the case?

Again thank you guys for the help:)
 
Racerone,
Ive definitely not removed the high speed jets but i've passed a small wire brush wire in there and blew air after ive sprayed carby cleaner. seemed to be clean and unblocked.

But I think I know now what the problem is. Not sure how to fix it yet:(
After spending some time on youtube, I went back to check my motor and when I put the throttle lever down the timing rod doesn't move at all!! nothing!
I did try to move it manually on a water test and it made the motor run better. SO I think its definitely the problem.

Now i'm not sure whats causing it not to move with the throttle cable. both the throttle and the timing move freely by hand.

Any of you guys came across that? I see a big spring in there. maybe its not set properly? Is there instructions available to follow? or threads on here that shows how to install it? didnt find any yet:(

Bit annoyed having the boat sit in the yard while i'm on holiday! haha

Thanks again guys:)
 
After a bit of hunting around on google, looks like i've got to pull the flywheel off and lube the insides of the timing 'thing' as the old grease gets sticky...
Is this correct?
Also can anyone tell me what the specs on those 3 threads on the flywheel so i can put the correct bolts in and use a pulley puller.. Every bolt i had at home wasn't the right thread:(
 
Ok guys a little heads up, I've pulled the flywheel off, pulled the mag and re-greased the plastic ring located under (Whats that part called?) it sits in the magneto.

The advance rod now moves freely with the throttle. I did a quick test on the hose but i really need to hit the water to be sure if its solved the issue.

Thx for the help:)
 
What is the model number of that engine?

What spark plugs are you using... make, # type, gap used?

Free the timer base... Clean, new grease on the brass bushing & just oil on the nylon ring...

Clean carefully the high speed jets with a piece single strand steel wire. The ID is only something like .030 so a brush can't be poked through them!

(Engine Won't Start or Hard Starting In Water)
(Joe Reeves)

The Evinrude and Johnson engines, starting in 1973, have what is called Magneto Capacitance Discharge ignition, self contained, not dependent on battery voltage. The engine must turn over at least 300 rpms in order for the flywheel magnets rotating past the stator ignition generating coils to supply approximately 300v AC to the powerpack(s), which in turn is needed to supply power to the coils etc etc (spark).

In the water, exhaust back pressure is encountered due to the fact that the exhaust housing (housing between the powerhead and the lower unit) is filled with water. This would drag down the needed rpms, affecting ignition.

Normally the clue to this type problem is that the engine starts fine on a flushette (hose), but is very difficult to start when in the water.

Should this be the case, check the battery, clean and tighten all conections (use a wrench or pliers, not your fingers). Any cable that gets overly warm or hot indicates either a loose, or tight but dirty, or internally corroded cable. And of course check the starter itself.
 
racerone said:
???----Post # 1 clearly shows the model #
Click to expand...

Racer...... Well, I'll be damned.... so it is. Model No 115693G <--- Whoops, there it is again! :cool: Vision's acting up it seems, time to quit the forums perhaps and get back to selling on eBay.

Anyhow... those old V4 models with Battery Capacitance Discharge ignition... the starter draws voltage away from the PulsePack. In order to have full battery voltage available to the pulsepack during the electric starter mode... rig a diode as follows:

(Voltage Drop To Battery Capacitance Discharge)
( Pulsepack When Electric Starter Is Engaged)
(J. Reeves)

On the older Battery Capacitance Discharge ignition systems (1968-1972), the electric starter reaches a point, even with a top notch battery, whereas the starter will draw excess voltage/current/whatever which results in a voltage drop to the pulsepack. The cure is to purchase a diode which is capable of handling 12 volts and installing it between the starter terminal of the starter solenoid (NOT the battery cable terminal) and the wiring terminal that supplies voltage to the pulsepack.

The diode must be installed so that the current flows from the starter terminal of the solenoid to the pulsepack... NOT vice versa. When that diode is installed in this manner, when the key is turned to the start position, the voltage that is applied to the starter is also applied directly to the pulsepack via the diode effectively eliminating the voltage drop and energizing the pulsepack with the required voltage needed for its proper operation.
 
joereeves
yes details are on post #1. Anyway

Model No 115693G
Serial No A312078
Pulgs NGK B7HS 10

The water starting issues is more like.. Motor turns (1sec) starts but instantly dies. Do this about 6-7 times and then idles barely..

Im heading on the river in a few hours, Will report back now that the timing arms moves when throttle is applied.

Also, Could anyone help me figure out the impeller kit needed for this motor so i can hunt one down on ebay?
Parts are very expensive here in Australia form shops:(
 
Great news everyone.. Boat hit 42knots today.. So happy!! not the smoothest running engine but seems reliable enough! starts easy, holds idle and goes well. Might need a fine tune but i've got no idea how to do that??
So it was definitely the nylon ring that had dried up and stuck to the timer base.

I think the water pump needs attention. Water coming out of the two rear holes on the leg isn't boiling but quite warm and straight from the start and pretty much stays the same. Do these have the tell tail or just those two rear facing vent holes (not sure what its called).

So yes would appreciate if anyone had the part number for the impeller kit:) thx
 
Guyph_01..... On your 1969 model V4, the rectifier is most likely on the rear portion of the engine above the Pulse-pack.

(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue
********************
(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.
 
Hey guys,
Ive decided now that it runs ok to replace the water impeller on this old motor. who knows when its been last done. I had a look on youtube but i can't find any info on how to disconnect the gear pin. Everything on youtube is the type that has a bolt. This engine is different and has some sort of pivot arm that is linked to the shaft. And i cant figure out how to disconnect it. Joerevevs Please help:)
 
???--So are u sure it is a 1969 model ?----Any pictures of this motor ?------A 1969 model would have electric shift.----No gearshift pin.----Has an expensive electric cable that needs to be disconnected and looked after.
 
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