cuts out at wot

buggyman20 · Jan 27, 2012

I have a 1989 johnson 120 hp. I just recently rebuilt the carbs. It starts good and runs great up to 3/4 throttle. From there to wide open it starts to cut out and run rough. Back off to 3/4 and it runs great again. I need help. Any ideas.

andrewddrennon · Jan 27, 2012

Re: cuts out at wot

1. Check spark and compression, youll need a spark tester and compression guage.
2. Run it on a portable gas tank with a new fuel line and bulb.
3. If you dont find a problem there you may have missed somthing in your carbs, or maybe a bad fuel pump.

Did you have the same problem before you rebuilt the carbs? If so I would look at number 2.

buggyman20 · Mar 3, 2012

Re: cuts out at wot

I replaced all gas lines and bulb, found some cracks in the old lines at the connections. The compression is #1 and 4 are at 120 psi #2 and 3 are at 110 psi. Took it to the lake today and would not start. Checked it at home NO SPARK. Pulled out the manual and checked what I could still no spark. Took a guess and pulled the safety switch. Checked it by the manual with multimeter. Sometimes it worked sometimes it did not. I ordered another one. Anymore ideas would be helpful.

SparkieBoat · Mar 3, 2012

Re: cuts out at wot

link for a dva adapter is in my link below along with a free trouble shooting guide.

buggyman20 · Mar 4, 2012

Re: cuts out at wot

Is there any way to bypass the kill switch to check for a spark with a spark tester?

j_k_bisson · Mar 4, 2012

Re: cuts out at wot

Yes there is. Dissconnect the main wiring harness. You will not be able to stop the motor without reconnecting the harness. To start junp at the solinoid. Shoud start. If not, open the primer valve for the fuel, be prepared to shut the valve after you have it running. Use the valve as a choke.

boobie · Mar 4, 2012

Re: cuts out at wot

Disconnect the black/yellow wire at the power pack. If you have spark, boat prob. No spark, mtr prob.

buggyman20 · Mar 4, 2012

Re: cuts out at wot

I have no fire to the plugs. I have a service manual and have gone through the steps I can. I do not have a PRV meter and wonder if it is worth spending the money to fix a 22 year old motor. I have done the output test in the manual. I have gotten to the charge coil test and can not go any farther due to lack of special equipment. Also the floor in the boat is a little spongy. Thinking about buying a newer used boat. Any suggestions on a good motor?

CharlieB · Mar 4, 2012

Re: cuts out at wot

With that much compression that motor has a lot of life left in it, someone will want it if you don't want to spend the time or effort in figuring out what is wrong.

buggyman20 · Mar 4, 2012

Re: cuts out at wot

One of the biggest problems I have is finding replacement parts. The last part I had to buy came from Australia. None that I could find here in the states

SparkieBoat · Mar 4, 2012

Re: cuts out at wot

there is an abundance of 80s model OMC parts in the US. about 20 places come up as soon as you google omc outboard parts. 89 johnson is a great motor and well worth fixing.. instructions in my sig below

buggyman20 · Mar 4, 2012

Re: cuts out at wot

There are a lot of obsolete parts. Do not know where to find used parts. Those instructions are the same basic ones as in the service manual.

SparkieBoat · Mar 5, 2012

Re: cuts out at wot

there is NOT any obsolete parts on a 1989 120 johnson (or any other late 80s model OMC) that I am aware of, every part for that motor is still in current production and there are a lot of them out there. there is a list of bone yards in the secret files section. But I highly recommend NEW CDI replacement parts for all electronics.

archcycle · Mar 5, 2012

Re: cuts out at wot

buggyman the DVA adapter in SparkieBoat's signature is an adapter to turn your multimeter into the PRV that you need to test the ignition.

Go here for parts diagrams and part numbers:
http://shop2.evinrude.com/Index.aspx?s1=le942fh1v8oum4gpk2svld92b2&catalog_id=0&siteid=1

You can buy the parts from places like right here on iBoats, some place about boating that ends in a .net, and MANY others. Just remember when searching that sometimes people leave off the leading Zero on the part numbers which makes a difference when you search places like eBay.

If you have a BRP/Johnson/Evinrude dealership near you they will have the parts although you'll pay a premium compared to online.

buggyman20 · Mar 5, 2012

Re: cuts out at wot

This is the part I could not find.
http://shop2.evinrude.com/Index.aspx?s1=ljiv1uv4g3kk0g7dptbpo5fci4&catalog_id=0&siteid=1
Part number 0432095 Link Assy. Spark Advance That is just one part that I have found not available.

buggyman20 · Mar 5, 2012

Re: cuts out at wot

Is that for an analog meter or a digital meter?

buggyman20 · Mar 5, 2012

Re: cuts out at wot

How does the DVA adapter work on a digital meter?

will62 · Mar 5, 2012

Re: cuts out at wot

This company shows to have one of the link assemblies in stock:

http://www.gunnellsmarine.com/parts spreadsheet omc.php

The DVA adapter connects to a digital meter. It accumulates the charge in a capacitor, then releases it, allowing the DMM to measure a peak voltage, rather than an average. If you have an analog meter, you can measure the peak voltage without the adapter.

SparkieBoat · Mar 5, 2012

Re: cuts out at wot

you can most likely find new linkage parts, but a lot of people get used ones..ebay is a great source

buggyman20 · Mar 6, 2012

Re: cuts out at wot

How do you measure the peak voltage with an analog meter. The service manual says you have to have a special meter

cuts out at wot

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