1994 Johnson 120 V4 - problems

[BCorn]

I bought a 15 year old boat a few weeks back. It has a 1994 Johnson 120.
Before buying the boat I listened to it run (on cups), checked
compression, inspected plugs and engine for any obvious problems, made
sure it started easy (cold as well as warm), verified that water pump
was pumping, etc......I was told that the boat was ready to go and
thought that I had had checked it over adequately. The first time a ran
the boat in the lake everything seemed okay except that it would not
idle.......seemed to simply be idled down too low. The guy I got the
boat from said the boat had sit a while and the gas may be old...so I
drained the gas best I could and put in fresh. Took it to the lake again
and still no idle. I can also hear one of the (possibly more than 1)
carb.'s "spitting" back.....i.e...."pfft, pfft, pfft". Also, when
running at higher RPM's the boat is stalling some and will not rev above
4,000 rpm's. At higher rpm's I am 98% sure I am hearing a slight "chirp,
chirp, chirp" alarm coming from the key area. It is hard to hear because
it only does it when the engine is running high rpms (loud) and stops
when letting off throttle. It is not the same loud beep that briefly
alarms (1 or 2 beeps) at initial start up. The VRO is still connected to
this boat and seems to be functioning fine. I think my problem is fuel
or air/fuel ratio related. Maybe running a bit too lean is causing it to
"sneeze". I have read about S.L.O.W. mode that limits rpms if the engine
is overheating....I am not sure if this is the problem or not. I would
like to know your thoughts on this. Thanks so much.

[ezeke]

S.L.O.W. should be accompanied by a constant horn warning from the control when activated by overheating. By the time that happens you need to shut the engine down immediately and not run it until the source of the problem is corrected.

The horn sounds short beats every 20 seconds +/- when there is LOW oil,
and continuous short beeps when there is NO oil. S.L.O.W. is isolated from the oil alarms by blocking diodes in the main engine harness, but if there is an oil shortage, the engine will overheat of course.

The idle RPM on your warm engine needs to be set in gear on the water, under load to near 650 RPM. You can get close by adjusting to around 800-850 RPM with no load. Be sure that quikstart has released before making any adjustments to the idle.

Loopers cannot stand running cold and will not idle properly if the thermostats are not working correctly. At low speeds they are sensitive to fouled recirculation check valves and dirty spark plugs.

Your engine will thrive on a good TC-W3 oil with constant carbon treatment such as BRP Carbon Guard or use XD-50 oil whiuch has the carbon treeatment built in.

[BCorn]

I sure hope I havn't already screwed something up. I bought the boat a week before a Memorial day fishing trip. As a precaution I took the boat to the shop to be thoroughly checked over (and idled up). $220 later the guy told me everything was great on the boat, but as stated above, it still ran poorly.

I have been doing some reading on here about the different alarms and I am confused about what I heard on my boat. As mentioned above, the "chirp, chirp, chirp" noise that I heard was very subtle and was no wear near as loud as the "bee, beep, beep" that I get upon initial start up. In my reading on here, I can't find any description that matches what I heard. I am concerned the the alarms have been altered.

[ezeke]

That's a no oil alarm and can be caused by a clogged oil filter (in the oil tank), air in the oil line etc.

The initial test alarm is from wire running directly from you ignition switch to a third wire on the horn. The wire that runs to the actual alarm is small gauge and has to come from the engine source, so that the ground is easily compromised by distance and corrosion.

The overheat alarms' switches are in cylinder heads with the tan wires running from them. You can test the horn circuit by disconnecting one of them and grounding the remote end of the tan wire to the engine block with the ignition on. That will let you hear the volume that you would normally expect. There will be a quick disconnect a few inches from the cylinder head.

Occasionally, the tan wires are running too close to a spark plug wire and that can sometimes cause a little noise.

[BCorn]

is that a filter the i can easily get out of the oil tank? If so, I will yank it out and install a new one. As far as the air in the line.....what do I do about that? The tank does have a primer bulb. Can I solve any air bubble issues by simply squeezing the primer bulb?

What is a "looper" as reffered to in the above post?

Af far as the engine running crappy, maybe I should try new spark plugs. How do I check for fouled recirculation check valves?

[ezeke]

Here's the story on the 2 stroke loopers and crossflows: http://www.maxrules.com/fixtheory2.html

The check valves are connected to small hoses running from the side of the cylinders. You can usually clean them up with alcholol, but if they get clogged they will need replacing. The valves are somewhat accessible on the starboard side, but you need to take the fuel pum off to get to the port side. I would do that as a very last thing after a thorough de-carbon treatment since that often clogs them up again.

I think you will get your best performance using the recommended surface gap plug - the Champion QL16V.

If you have an air leak anywhere in the fuel system, you have to close it. Air in the line causes the pump to pull air when it needs to get oil or gas. It also can cause the engine to run lean, which means too much air and not enough gasoline; that can overheat the engine and literally melt a piston.

[jonesg]

I have the same engine, same yr, it helps to get the factory service book and read up about all the systems. Its the best $45 you can spend at this point.
www.outboardbooks.com
The oil line should be purged if it has air in it, if in doubt mix oil in your fuel until oil use is verified by keeping track of the oil level. I'd mix oil in the fuel until I figga out what that chirp is all about.
Purge oil line by disconnecting and pumping bulb until solid oil comes out.
Disconnect oil line by pushing it off the fitting, don't pull.
Make sure the lines are clamped.
I just bought a temp guage for mine, I just like peace of mind.

Hey zeke, my manual says Champion QL77 type plug, did they change the recommendations?

[ezeke]

Look up the cylinder and crankcase for the 1994 120HP on the BRP site, then select the spark plug on the diagram. Also verify with your dealership. Details: Part Number:0432424Description:QL16V-PLUG 4PK Pack Qty:8Dimensions:3.50 x 1.00 x 0.88 (in)Weight:0.13 lbsEquivalent Parts:0502178
http://shop.evinrude.com/

The only plug listed for the 1994 120HP Johnson is the QL16V.



Details: Part Number:0432424Description:QL16V-PLUG 4PK Pack Qty:8Dimensions:3.50 x 1.00 x 0.88 (in)Weight:0.13 lbsEquivalent Parts:0502178

[jonesg]

ahh, mines a 150hp, BRP calls for the QL77.

[BCorn]

As stated above, after purchasing the boat I put it in the water for about 30 minutes and it seemed like everything was good with the exception of idled too low. I brought it the the shop and told them that it seemed to be idled too low but to also check everything out really well because I did not know the boats history and I had a 3 day fishing trip coming up. I felt like if I had it checked then I wouldn't worry so much about running the motor and possible messing something up....ecspecially if there was only a minor problem that needed attention. My invoice is as follows:
(4) 332253 Seal, carb...............$3.21.......$12.84
(2) 332319 Gasket, throttle body $2.45......$4.90
Gear Lube.............................................$ 15.00
total parts............................................$ 32.74

Removed carb; checked
carbs-ok; replace carb seal & throttle
body gasket..........................................$1 25
drained gas...........................................$50
total labor...........................................$1 75

total labor and parts..............................$207.74

when i first got to shop the machanic ran the boat and it sounded bad....he said that it had run great the night before. I got my money back and left boat there. picked it up later and he told me that he just had it running too rich. he ran it and it sounded good. i paid him and left. when i got to the lake i had the above mentioned problems.

[fergie]

Hey do a quick check and make sure your throttle advace plate is moving and retracting with the butterfly's i have an 85hp v4, had simular issues, i found my timing advance plate was sticking.

[BCorn]

update: brought it back to mechanic and explained probelm.....he just called and said he thinks it is the reed plate gaskets. he said those are back behind the throttle body gaskets that he just replaced. he said that he feels confident that this will fix it. what do ya'll think? does this seem like a good diagnosis?