High RPM surge driving me nuts!!!

[Faztbullet]

Check the high speed jets for being loose as they vibrate in and out if so.

 

[racerone]

Shine a strong flashlight into each carburetor bore and observe amount of fuel coming up each nozzle.----Done at full throttle out on the river.

 

[racerone]

edited

 

[summer lake lover]

Already know it’s not fuel guys, observed spark dropping out randomly on either bank. Racerone, I agree a lot of electronic parts probably are replaced on a hunch, I don’t have a DVA meter, so all I can really check is resistance with the engine off, (I don’t even know how one would go about checking anything back there with the engine running, it’s tight!!!) The only thing I saw was relatively low stator resistance, which is where I’m leaning the problem is, I’m just curious in your opinion if the trigger pickup should be replaced while I’m in there, or if they’re not very prone to having issues on the 130 Evinrude V4’s, I’ll leave it be, thanks much again in advance!!

 

[racerone]

Sorry-----I am stepping aside.-----Should spend my time overhauling the 1997 model 130 HP that I Have laying around.

 

[Crosbyman]

see page 52 and onward for 4 cyl 1998 130hp trouble shooting guide

https://www.cdielectronics.com/wp-content/uploads/2016/12/7th-Edition-Troubleshooting-Guide_RS.pdf

 

[Crosbyman]

a dva meter is a regular DC volt meter with common diodes and capacitors hooked up to measure peak voltage generated...

if you search the web you can find easy to build circuits you can wire up. no need to buy expensive DVA meters

see post#6 in this link

how to make a DVA adapter for multimeter

Someone (starts with BK and ends with THEKING) responded to a question about how to make a DVA adapter and sent a link to directions. but the link has been moved or deleted it said. Does anyone have those directions.....? I gotta miss in this 81 Johnson V-4 and I gotta find out why.

forums.iboats.com

 

[summer lake lover]

Hey thanks much Crosbyman!!! Let me ask you this, checking resistances, I found the stator right at the lower end of the scale, which is making me suspect it, If I can prove its bad with a dva test, while I’m in there would you replace the timing base as well, or are they not very prone to failure?? I see the voltage they generate is much lower than the stator.

 

[oldboat1]

Repurposing a timing light to check spark is an old trick (gives you a way of checking spark while driving the boat). No flash, no spark. You still must measure spark, though, if you have it. Use an adjustable open air testing device (cheap) -- testing ignition strength. Another useful trick is using an IR heat gun to check for shorts. If you have ever burned your fingers touching a shorted/corroded battery cable, you know how much heat can be generated. Use a 50:1 premix. As you probably know, OMC advised 100:1 for a brief period, but reverted to 50:1 for overall running. On the other hand, too much oil in the mix could give you the surge condition which you describe, and may do nothing for you anyway other than mucking up plugs.

 

[oldboat1]

(double post)

 

[racerone]

I do not believe larger OMC motors were ever meant to run at 100:1 mix.----It was a brief exercise by the board room in the mid 1980's to run the 6 and 8 HP / and 9.9 to 30 HP on 100:1 mix

 

[summer lake lover]

Yep, I use an infrared thermometer for checking electrical connections at work, power companies use infrared cameras for finding bad connections in the power lines, I had never heard of or thought of the timing light trick until Racerone let me in on it. I normally run all of my two strokes at 32:1, I figure spark plugs are cheaper than rings and cylinder walls LOL

 

[Crosbyman]

Hey thanks much Crosbyman!!! Let me ask you this, checking resistances, I found the stator right at the lower end of the scale, which is making me suspect it, If I can prove its bad with a dva test, while I’m in there would you replace the timing base as well, or are they not very prone to failure?? I see the voltage they generate is much lower than the stator.

although I have provide info for you I would not be in a position to have you spend $$$ on expensive parts as I am not a full fledged mecanic like Racerone and others . My field of expertise was telecoms not outboards

hopefully the DVA test adapter will help you decide as well as the CDI manual

 

[summer lake lover]

Yeah, I hate to spend money needlessly either, especially nowadays, I’ve got a DVA coming with some probes to make it easier to test, thanks much for the guidance to the testing procedure, I’ll run it down and go from there. If the timer base isn’t bad, I almost hate to replace it with the stator, but it’s right there, I don’t know if it’s got a high enough rate of failure to replace while I’m in there or not. I saw CDI makes some “redesigned and improved” ignition components that they claim are superior to OEM, is this the brand most people are choosing?? Thanks much again in advance for all of your help guys!!!

 

[oldboat1]

VRO lubricates at 50:1 at higher rpm. 32:1 will lead to loading up in your motor and poor running.

 

[summer lake lover]

Thanks for that info. oil isn’t cheap anymore either. I am still waiting on my DVA to arrive to nail down a component, and another interesting thing I’ve found is there is an air gap between my throttle roller and ramp, the roller looks small to me, it’s maybe 1/4” in outside diameter (about the same diameter as the O ring retainer), is this normal??? Thanks again in advance!!!

 

[Keyboardman]

Thanks for that info. oil isn’t cheap anymore either. I am still waiting on my DVA to arrive to nail down a component, and another interesting thing I’ve found is there is an air gap between my throttle roller and ramp, the roller looks small to me, it’s maybe 1/4” in outside diameter (about the same diameter as the O ring retainer), is this normal??? Thanks again in advance!!!

Looks like the actual rolling part/sleeve is missing off the roller post. Held in place by a small O ring or C clip?

 

[summer lake lover]

There’s a black roller on the post, it’s just not very large in diameter (only about 1/4”), and it’s held in place by a little O-ring on top, is there an outer piece of the roller missing, or is that all there should be? And should there be an air gap? Thanks much in advance!!

 

[Crosbyman]

 

[racerone]

At idle the throttle plates are to be CLOSED.-----Idle speed is then controlled by timing.-----So there is usually a gap there.-----Do not start adjusting things unless you are absolutely sure that some thing is wrong.