120 Looper Problem almost fixed! Please advise!

[jesseoshea]

1989 Johnson v4 120 Looper

Compression 120 +/- 3 on all cylinders
New Rectifier
New Power Pack
All new fuel lines/tank

This motor has been great for many years, but recently has been giving me a fit! It started with a mild hesitation at WOT like a minor skip and then progressively got worse to the point that it wouldn't plane out or even idle properly. I noticed that the voltage would drop off then spike so I replaced my rectifier yesterday. I also replaced the PP but did not replace the stator (couldn't get the flywheel off to save my life). I tested the boat yesterday (2 hours) and it ran absolutely flawless! Perfect at every RPM including idling and WOT. I was really excited so I took the boat out today and it started all over with the same type of problem (after about 20 minutes of use). It began with a slight miss or loss of power at WOT and then progressively got worse to the point where I could hardly idle back to the dock. It was also smoking excessively (I mixed perfectly, I promise!). The plugs were wet and oily (all four) and it had a definite miss. I am trying again to take the flywheel off to replace the stator (used pb blaster overnight, tightened puller with impact wrench, let sit over night with tension, and even hit the top of the puller with a hammer at last resort with NO luck). Please reassure me that it can be the stator! The primer bulb never got soft (pumped it while having the problem, just in case). It definitely seems like it has fuel. I have a DVA adapter and a Fluke meter. I will try to test my PP, stator and coils tomorrow (not exactly sure how, but I will look it up).

ANY advice would be greatly appreciated! Thank you in advance!

 

[jonesg]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Did you try a spark GAp tester and a timing light to find any dud coils ?

 

[tashasdaddy]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

ethanol poisioning? http://forums.iboats.com/showthread.php?t=299680

 

[jesseoshea]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

I am going to test the coils and rebuild the carbs now! Will respond in a few hours!

Thank you!

 

[PSiedTSi]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

I am going to test the coils and rebuild the carbs now! Will respond in a few hours!

Thank you!

I am(was last year anyway), having a similar issue. I am definitely going these routes before getting nervous .

 

[Andre]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

If you're having trouble popping off the flywheel and you're at the point in your testing that will require it, call your local marina and see if they'll pull it off for you. It might cost a couple bucks but will save you a few headaches in the process.

Andre

 

[jesseoshea]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

I rebuilt the carbs with Sierra kits, but the carbs looked perfect when I pulled them off. There was absolutely no trash, gunk, sand or anything in them, but still cleaned them thoroughly and rebuilt them. I also replaced all of the fuel lines that were connected to the carbs (all other lines had previously been replaced). I did however find that one barb on the primer solenoid was broken off (not sure if it occurred when removing the carbs or if it had been that way before). I'm thinking maybe it was broken previously because there was a reasonable amount of oil/gas in the bottom of the air box. I also tested the coils which tested fine. I finally got the flywheel off and replaced my stator. I will water test tomorrow (didn't have time after work today unfortunately). I was just curious, about how long should it take for the engine to die when applying full choke while the engine is idling? Currently it takes about 4 seconds. I realize 4 seconds seems fast but it is actually a long time compared to my seadoo's, which take about 1 second, but they also have a choke butterfly. The engine seems to be running perfect, but I can't really tell until I water test it.

I will update tomorrow afternoon if the problem is solved. Thanks again!

 

[CharlestonMako]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

I also tested the coils which tested fine.

How did you test the coils?

Where are you getting your parts?

I am having similar problems with mine... good luck... hopefully youve got it figured out.

 

[jesseoshea]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Update:

Water tested today. Worse than before.

Spark test @ 7/16" all passed perfectly. Pretty blue spark
Coils tested well with ohm test too.
All electronics replaced except coils and timer base (stator, rectifier and PP)
Also tested at night to see if anything was arcing --- All was well

Engine sounds pretty bad. One thing I did notice was that with the timing light on each wire, the top left cylinder seemed to be firing twice as much as the other three. I don't know a better way to describe it except that the frequency of the light strobes had to be nearly double, but all of them seemed fine otherwise.

I have not replaced or checked my recirc valves, but I'm going to replace them tomorrow. At this rate I think I will replace all of my coils just because. I will also attempt to decarbon the engine.

 

[tashasdaddy]

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

Re: v4 120 bogs, cuts off, misfires, wet plugs! stator?

double firing is usually power pack, you only have one on that motor.

 

[jesseoshea]

120 Looper Problem almost fixed! Please advise!

Had major problems with arcing coils that could only be seen at night with complete darkness.

Replaced coils and wires. Cleaned all grounds including coil grounds and main engine ground. Engine ran much smoother.

Boat ran fantastic for 35 minutes before it started to hesitate again. This time I think its fuel related. My buddy borrowed my main prop and I've been using a severely over pitched prop (my spare). WOT @ 4200 rpm (but still 54 mph GPS). This engine is supposed to run 5500-6k. I am fairly certain this is the cause of my final problem. After running great for 35 minutes the engine began to slowly lose power and had a hard time idling. All while smoking badly! My theory is that since the carb butterflies are open fully but the engine isn't making the RPM it is trying to, that the engine is running extremely rich ---- causing severe rich issues (plugs are soaking wet) and terrible idling problems (hard to keep running near the end of my trip). It would idle lower and lower then die. Is this possible? The boat however would still plane out and run great for the most part.

(BTW I still have very minor "leakage" around one spark plug boot and coil to the mounting bolt. I have tried numerous different wires (had all four extra ones and tried known good ones). What can cause this? It has all new Johnson OEM plug wire assembly kits. In fact I had leakage on 3 of my brand new wire assemblies and coils but using two of the original wires fixed the problem. They ohm test perfectly. The spark would actually jump from the plug tip to the base of the plug (metal part). Please, any advice on the plug leakage or rich issue would be appreciated.

Thank you!

 

[jonesg]

Re: 120 Looper Problem almost fixed! Please advise!

Loose timing wheel can cause dble spark, make sure it has the wave washer to keep it in place.

wet plugs might be caused by the escaping spark, if it arcs it probably isn't going to fire the plug too well.

what plugs are you using , what gap?

Try to apply a smear of dialectric grease to the plug boot.

Its lugging, probably running hot, take it easy with that oversize screw.

 

[jesseoshea]

Re: 120 Looper Problem almost fixed! Please advise!

According to the FSM I'm using the correct plug and gap. QL77JC4 @ .030"

If I understand you correctly I assume you're referring to the timer base? If so I haven't touched it other than Ohm testing and DVA output test. Everything tests good. I will apply the Dielectric grease on all boots and connections.

Can the over pitched propeller be causing the cases to "load" up so to speak (fill up with fuel and oil)? If so I think it would explain the excessive smoking, poor idling, and wet plugs.

Engine runs cool. It's an oversized prop but an extremely light boat. Runs at 120 degrees or so. warms to about 160 when idling

 

[jonesg]

Re: 120 Looper Problem almost fixed! Please advise!

According to the FSM I'm using the correct plug and gap. QL77JC4 @ .030"

If I understand you correctly I assume you're referring to the timer base? If so I haven't touched it other than Ohm testing and DVA output test. Everything tests good. I will apply the Dielectric grease on all boots and connections.

Can the over pitched propeller be causing the cases to "load" up so to speak (fill up with fuel and oil)? If so I think it would explain the excessive smoking, poor idling, and wet plugs.

Engine runs cool. It's an oversized prop but an extremely light boat. Runs at 120 degrees or so. warms to about 160 when idling

yeh I think that prop could be causing all sorts of symptoms, and new ones soon if you don't ditch it, let your buddy use it

"excessive smoking, poor idling, and wet plugs."

those are all symptoms of cold running, either the prop causing it or thermos stuck open( its the prop), you might want to seafoam decarb it too.

 

[clanton]

Re: 120 Looper Problem almost fixed! Please advise!

Have you check the voltage output of the timer base, stator, and power pack, with the peak reading meter.

 

[clanton]

Re: 120 Looper Problem almost fixed! Please advise!

This engine has Quick Start, I think. You need OEM manual to check the timer base. Very different the standard timer base.

 

[Pokertrampp]

Re: 120 Looper Problem almost fixed! Please advise!

Guess we do not know how this was resolved...