Johnson 135 surging

[younggun]

I have an older carbureted johnson 135 and when I took it out today it took off and did good for the first 1/2 mile or so but then started surging at full throttle but would do fine if backed off to about 3/4 throttle. The surging kept on but then the motor wouldn't do anything. I would crank it up with the fast idle on and it would fast idle for a little bit and then die out. We tried to pump the priming bulb and it didn't seem to help much. Any ideas as to what could be causing this?

 

[phillnjack2]

Re: Johnson 135 surging

dirty carbs
maybe a bit of crud got into one of the fuel lines or inside of main fuel pipe is going bad.
the new fuel nowdays rots the older style pipes very quick from inside out.
what often appears to be nice fuel pipe is totally breaking up on the inside !!!!

phill

 

[younggun]

Re: Johnson 135 surging

I should have put that the carbs were just removed and cleaned a few weeks ago but should I check again? I always run no ethanol fuel in my boats too to try and prevent the line breakdown.

 

[HenryB]

Re: Johnson 135 surging

The motor sounds like it is starving of fuel. A bad primer bulb will do what you describe. Did you notice if the bulb was flat when the starving occurred? If the bulb does not flatten, and you have a clear in-line filter, watch it when it is running without the surge and while the surging is happening. The problem could be a bum gas tank vent line or a bad pickup tube. Perhaps a piece of clear tubing between the bulb and the filter might tell you something. And take a good look at the piece of tubing that you removed to see if it is breaking down.

And something else, both the vent line and the pickup tube have check valves, especially the pickup tube. Check valves do fail. The check valve is screwed into the elbow at the gas tank. You can take it out (if it cooperates) and reattach the line. If no surging replace the valve. probably a good idea to change the valve anyway.

 

[Bosunsmate]

Re: Johnson 135 surging

what years this?
You can often isolate it down to a particular cylinder/ carb by doing a drop test.
How did you get back to ramp?

 

[younggun]

Re: Johnson 135 surging

It is a 1973. I got back to the ramp thanks to the trolling motor. I used two different portable tanks and it acted the same on both. I also use the tanks for 2 other motors and they run fine with them. What is the proper way to do the drop test?

 

[Bosunsmate]

Re: Johnson 135 surging

I dont know what the proper way is.
BUt what i do is run the motor til its warm and then pull off a cylinders spark lead in turn. You should notice a similar drop in rpm per cylinder. If you dont notice a drop that cylinders probably dead.
Best way to do it is in a drum not on muffs.

I rebuilt a 90hp the other day, i told the guy to try and run it on the top and then the bottom cylinders each time he pulls it out of storage. If its doesnt run on either one on the muffs then he can isolate the problem down to either top carb or bottom carb, (and also electrics if its not sparking)

 

[emdsapmgr]

Re: Johnson 135 surging

Recheck for spark. Any spark test is best run after the engine has been running for a while. Weak ignition parts don't like heat. An engine that has weak ignition components may fun fine when cold, then when the engine is warmed up-the weak component can crap out. (once the engine reaches it's normal operating temps.)

 

[younggun]

Re: Johnson 135 surging

I talked to a family friend mechanic and he said it sounded to him like the rectifier was shorting out or had a loose connection. Does this sound right.

 

[emdsapmgr]

Re: Johnson 135 surging

The rectifier is part of the electrical charging system, not part of the ignition system.

 

[younggun]

Re: Johnson 135 surging

I did the cylinder drop test and everytime I unhooked the number one cylinder the engine would cut off and wouldn't hardly change on any of the others. I noticed when I pulled one and held it close to the block that it had intermittent spark. It would spark a few times then stop and then do it again. The motor would completely die out everytime the number one cylinder boot was pulled. I allowed the engine to warm up before I did this also. What does this mean and what do I need to check next?

 

[racerone]

Re: Johnson 135 surging

Start with posting the results of a compression test.

 

[younggun]

Re: Johnson 135 surging

1-158 2-150 3-150 4-148

 

[Bosunsmate]

Re: Johnson 135 surging

Check your stator
And then the other electric components
ISSUU - CDI Electronics Practical Outboard Ignition Troubleshooting by CDI Electronics

 

[HenryB]

Re: Johnson 135 surging

If you pulled #1 plug wire and the engine stalled it probably means that #1 is firing. Test again, pulling one plug at a time, and if there is a plug not firing you should see little or no rpm change. Get a cheepo-beepo spark tester at the local auto shop that has an adjustable air gap, set it to 7/16, and test the plugs in the evening when you get the brightest results. If it is a plug firing intermittently the engine would bog quite noticeably even at 3/4 throttle.

For a '73 engine those compression readings are remarkable.

 

[younggun]

Re: Johnson 135 surging

Thanks for the link. According to that it looks like the rectifier may be the issue. I may take it to our family friend and have him walk me through the ignition process so I can see hands on and learn about it(only a teenager who is learning the ins and outs of outboards).

 

[HenryB]

Re: Johnson 135 surging

A fuel pump repair kit on ebay under 15 bucks.

 

[younggun]

Re: Johnson 135 surging

Thanks for the replys. As the engine got warmer it would surge and as it got close to operating temps it would bog really bad and not even plane.

 

[emdsapmgr]

Re: Johnson 135 surging

The rectifier is part of the stator's charging system. It is unrelated to the ignition side of the stator, which appears to be where the problem you having originates. You can get some excellent ignition troubleshooting information from the afore mentioned website: cdielectronics.com. The website offers specific qualification requirements to test the stator, timer base, with the help of a special peak-reading voltmeter. The stator, timer base, power pack are all expensive components. Rather than just jump into replacing each of them- it's to your economic benefit to do some testing. Another thing: weak ignition components tend to work ok when they are cold. Once the engine heats up to normal operating temps, weak components can start to fail. Sounds like you may be experiencing exactly this. Do your testing when the engine is warmed up. You can swap a couple of coils to determine if the non-firing cyl changes with the coil swap. (it may not) A timing light is a handy too to check for spark on each plugwire. Then test the timer base and stator. If they check out, the power pack is the last component. From a purely statistical standpoint, it is most likely to fail. (in my estimation,it's not a good enough reason to just go out an purchase a new one right away.)

 

[younggun]

Re: Johnson 135 surging

The first thing it says on there for one or more cylinders not firing is to unhook the yellow wires on the rectifier and if that solves the problem it needs to be replaced. I was just going by the website. Thanks for all of the help.