480CE RPM jumps 100-200 every now and then ?

[Greg Weaver]

Hello all, 2003 Carolina Classic 480CE

I have searched the forum here and google and have found similar issues of rpm dropping but my hiccup is it jumps up some.

I have had this problem on and off for a year now, it comes and goes.
It will not do it at idle in the slip.
It happens when i’m trolling at low rpms
I turned my engine sync off and have isolated it to the starboard engine 100%.
Racors are checked daily as I charter the boat and it is part of my routine check EVERYDAY
Racors are crystal clean
Last chance filter is brand new and last year i had the problem prior to changing it and directly after changing it

I watch my rpm jump and the recover moments later and I also feel it in the seat of my pants.

Port engine is a fresh rebuild with 600 hours on it, no black smoke at throttle up

Starboard engine has 2996 hours on it and runs like a sewing machine other than this hiccup
Starboard engine has some black smoke on throttle up, unless I bring it up really slow and it will have none

Props are perfect as per Tony’s fuel burn specs and both engines reach 2690-2700

It’s not a huge issue but when theres something not perfect, it bugs me and I would like to figure it out

My thoughts on possibilities are as followed

Also I might add, that all similar problems that i have read, are all starboard engine related.

Possible ground or loose wire?
Maybe a bad injector
Do these engines have a throttle position sensor ?
Throttle linkage looks fine

If anyone can chime in on things for me to consider I would sure appreciate it.

Thanks all

Greg

Topic

[Tony Athens]

OK & WOW!——You really do not know your boat—————————To me, that is scary….But, lets move on…..

You have Plain ol’ Hynautic controls designed in the 70’s–Quite reliable and built a solid reputation for decades——each lever operates a hydraulic “slave”. You have 4 of them on your boat, someplace… One for each gear and one for each engines throttle…………….You need to find the “THROTTLE SLAVES”………….They will look the the gear slave and both will have “something connected to them ( a cable or ?? ) We both need to “see” that “something”…

BTW, inside those 4 black plastic lines going “someplace” on your boat is pure Ethylene Glycol ( like antifreeze) –That’s the hydraulic fluid these controls operate on.. During you boat search, you should locate the pressurized aluminum reservoir that is a main part of this system.. You might need to know about it someday.

[Greg Weaver]

Tony,

Here are the pictures you requested

I don’t see any 33c cables coming from my controls.

is my throttle controlled electronically ?

Greg

[Tony Athens]

I want to “see” yous control head” or “heads” at the helm station.. Trying to figure out how your throttle is controlled

How many 33C type cable come from it?

[Greg Weaver]

Tony,

OK, I opened up the throttle %, pushed it very slowly all the way up to 100 and had no jumps or flat spots I watched every number go by until 100.

The cable that you wanted to no where it goes, it goes to the transmission

Pictures enclosed

[Greg Weaver]

Thanks Tony,

I will try to trace that cable and see what it connects to

And I can move the throttle up and watch the % rise, so I will do that in a few minutes and see what i see

If I see a jump or dead spot, what am I facing at that point ?

Thanks Tony

Greg

[Tony Athens]

You are getting closer…………

1) Look at the attached picture.

2) When in the “throttle position mode /screen”, you need to move the throttle very slowly and watch extremely close for any jumps or dead spots in the linearity of the % numbers.. Not sure if the older ED1’s have the resolution to do that

[Greg Weaver]

Tony,

I got a few pictures if more are needed just say the word of what.

Something tells me it it electrical related, just my feelings though

The boat runs like a sewing machine but this problems shows up every now and then, usually when I start trolling hangs around for a few minutes then goes away for maybe hour or so

Thank guys

Greg

[Tony Athens]

Pics of the displays too.

Do you have a mode or screen on the display that you can bring up ( ignition on, engine off) that shows Throttle Percentage as you move the throttle?

[Greg Weaver]

2003 displays I believe EDU

There is a 33c type cable

I will get good pictures tomorrow

Thanks Tony

[Tony Athens]

480CE———- RPM issues are low speeds

What exact engine controls do you have? Good pics please—————-Is there a 33C type cable that “goes someplace”? if there is, I want to “SEE” what someplace is..

[Author]

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