1992 Johnson 115 V4 Shuts off at WOT

[arnettjs]

All,
Brand new to boat ownership and to this forum. I just bought a 1992 18' Cajun with a 1992 Johnson V4 115 VRO outboard. Everything ran great during the test drive and two subsequent outings. However, yesterday on the lake the outboard began shutting off at/near WOT. This happened multiple times in a row until I finally slow-speeded it back to the launch ramp. The VRO tank is just over half full, new gas in built-in tank. No audible alarms are going off. Runs great at idle and slow speeds.

Being brand new to boating, I have 'dinged up' the prop pretty good. Its slightly bent on one fin and chewed up on the other two. Its a 13.25 x 17 aluminum, probably stock.

After researching many of the threads here (by the way, fantastic wealth of information!), I have learned that there appears to be an RPM limiter on most outboards (tach doesn't work but it did seem to be revving higher than normal when it cut out). Could the damage to the prop be causing the outboard to rev too much, thus the limiter killing the outboard? After it dies, it will immediately restart and run fine until I try to get up to full speed.

Other items that may be of help, the water pump pee stream is steady. Outboard starts without issue, either cold or warm. Fuel in tank is new. No visible signs of leakage at/around the outboard.

Before investing the $$ into trial-and-error (and subsequent furious wife), I'd love to narrow this down a bit. Any help will be greatly appreciated!

Sincerely,
Jeff

 

[ezeke]

Re: 1992 Johnson 115 V4 Shuts off at WOT

The probability is that you are overheating the engine, causing the motor to bind and stop - for whatever reason.

Take the tan wires at the cylinder heads, separate them at the quick disconnect a few inches out and ground the control ends to the engine block with the ignition key in the run position. This should sound the horn alarm. If it does not work, troubleshoot the alarm system.

Your best purchase at this point will be a OMC factory service manual that specifically covers your motor.
http://cgi.ebay.com/ebaymotors/1992...016QQitemZ260130232134QQrdZ1QQsspagenameZWD1V

You could also be running out of fuel in the float bowls at the bottoms of the carburetors. When this happens, there is no more fuel for the engine to pull through the carburetors so the engine dies. You can check this by having someone pump the primer bulb when the engine starts to quit.

A bent propeller will cause the propeller shaft, seals etc to wear. Best to replace it as soon as you can.

 

[arnettjs]

Re: 1992 Johnson 115 V4 Shuts off at WOT

ezeke,
Excellent information, thank you very much. I have a Seloc manual covering this OB but it doesn't have a lot of troubleshooting information. Hearing the prop isn't the cause is good news, as they aren't cheap and I'm sure I'll ding it up a few more times before I get comfortable with the boat. That being said, I'll definitely replace it.

After work, I'll attempt to ground the warning sensor wire and see if the alarm sounds. I'll post my findings.

Again, thank you very much.

 

[arnettjs]

Re: 1992 Johnson 115 V4 Shuts off at WOT

Quick update: The alarm system is working. As recommended, I disconnected the tan wire at the quick-connects (at the head) and grounded. Fairly audible beeping was heard. Also bought a new prop today and will install tonight. What is the proper torque? The manual says 75-85, other posts here say finger tight plus 1/4 turn (or too the opening for the cotter pin).

Did find a fuel line that was shaky at best. Rubber exterior was VERY cracked and it was loose. Air could have been getting in, replacing it tonight.

Am taking it to the lake Saturday to bass fish, will post any findings. Again, thank you, this forum has been SO HELPFUL for a new boat owner!

 

[emdsapmgr]

Re: 1992 Johnson 115 V4 Shuts off at WOT

Possible that you have a weak fuel pump. If the pump can't supply enough fuel to run top speed, it will abruptly slow at high rpm. Usually won't die and will idle fine. Once the pump refills the carb bowls, it will run till the bowls run short of fuel again. To check this, when it slows, pump the fuel hose bulb repeatedly. If the engine runs fine at high speed while continually pumping the bulb, the pump is suspect.

 

[arnettjs]

Re: 1992 Johnson 115 V4 Shuts off at WOT

All,
First, let me thank everyone for all the great information. Took the boat to the lake to bass fish yesterday and same problem. No alarm went off, RPMs simply fell off the chart at WOT. I immediately checked the fuel primer bulb and it wasn't rock hard, but it wasn't flat either. One pump to rock hard. No visible leaks anywhere. Hard time starting also.

I yanked one of the plugs to see if it was flooding. The plug was not wet and seemed to be burning fine (not excessively black, had a light brown color). When I did get it started, it wouldn't idle unless I had the throttle opened up a bit. Soon as I tried to drop it into gear, it would sputter and die.

I got a tow back to the launch ramp (quite a ways, some good Samaritan out there has no idea how thankful this boat owner is). Learned to trailer it with just the trolling motor. Called a boat shop and the guy said he'd need to look at it but it could be a stator or a power pack.

Frustrated that the day was a wash (co-angler did catch a nice 3.8 lbler though) but not giving up!

Seems electrical to me, as the OB doesn't loose one or two cylinders, it loses them all. Never 'misses' just doesn't retain spark at WOT then runs like crap after that. Will keep everyone posted, hopefully the shop's solution will help another angler.

 

[arnettjs]

Re: 1992 Johnson 115 V4 Shuts off at WOT

A quick update all:

I broke down, realizing I was a bit out of my league, and took it to a recommended shop. The boat is being fixed as we speak, according to the owner. There was a number of issues but two main ones.

First, the VRO unit was not working properly, barely supplying oil to the OB. We discussed options and the best was to bypass the unit and premix directly in the tank. One less thing to worry about! Second, the fuel pump was not supplying the necessary amount of fuel to the OB. This will be replaced with a new one. Third, The fuel solenoid was not working properly. This will also be replaced. Fourth, the carbs had some 'gunk' in them.

Finally, the voltage regulator was working intermittently. This was leading to charging problems and a tachometer that almost never worked (though once in a while, it did actually work).

My beloved bass boat will be ready in a few days and I'll lake test it (insert nervous look here). I do NOT want to get stranded a third time! I just want to catch bass!

I'll keep y'all posted, as this has been a bit of an experience for a new boat owner. I'm excited, though, and am expecting that my boat will be tournament ready. Oh, by the way....$870 was the damage. Ouch. There is a certain piece of mind in knowing that a pro found a number of things wrong that I couldn't have, at least not without time, effort, frustration, and special tools.

Keep your fingers crossed for me at the lake!

 

[jonesg]

Re: 1992 Johnson 115 V4 Shuts off at WOT

Everyone loves a happy ending, nothings worse than when the experts help someone out and they fail to report back the final resolution.

After hearing how much it would cost to have my 6 carbs rebuilt I got the manual and did it for $100 myself, get yerself that factory service manual, you'll save a ton, for more boat stuff.!
They can repair your dinged prop too.