Perkins V8 Idle Fast - PLEASE HELP

[Holding Pattern]

I've snooped through the threads but I can't bear it any longer so I have to post a question.

We have a 40' ketch, Perkins V8, usually idles about 1200 rpm, today, unexplicably, it was idling about 1700-1800 rpm. You could hear (though anyone not knowing it wouldn't recognize, I'm guessing) and I can't find ANYTHING that could be the cause. I have devoured Nigel Caulder's works, searched online ad nauseum, and I'm coming to y'all for help.

Although they are in no way connected, the voltage alarm meter for the battery was running high when we were on shore power, but that had no bearing & was separate from the idle speed/time. Methinks we need a new splitter for the shore power.

If you have an idea on the problem, you can email directly B_H_Rayburn11@yahoo.com or post here & I will check as often as possible though internet access can be ungodly slow.

thank you!

[Alan Wheeler]

Hi Brian, Wow! big engine for a boat that size. Hmmm, not sure exactly, but I would suspect the govenor in the injector pump.
By the way, even 1200RPM is a little on the fast side. Check your service manual, but I would have thought it should be more like 750RPM.
Which V8.xxx is it by the way.

[BC Mike]

Go to the Yanmar help line and do a search or ask the question. Two sources off the top, an air leak or it is running on engine oil. Check your oil level to see if it is going down, check the exhaust colour. Report this to the Yanmar help line.
Michael

[Alan Wheeler]

Hi Mike, umm, how would the Yanmar help line be any help with a perkins? Plus, what do you mean an Air leak. I can't think of anything that would leak air that would have an affect on a high idle. Plus, if when an engine is running on oil, it ain't a pretty site. Firstly the detonation noise is unbelievable and second, the world behind you disapears in a cloud of black smoke. The higher than normal idle would be the least of Brians concern
I am assuming Brain has checked the Morse control and throttle control lever on the pump, including the idle setting rest adjustment for position, so the only other thing that would allow normal operation and yet high idle is the injector pump govenor.

[CSY Man]

Would that be a Perkins 4-108 perhaps....?

Idle is easy to adjust on them things...Get a flashing strobe light and make a mark on the crankshaft pulley, then adjust the idle speed with the little screw on on top of the H/P pump.

The factory book says about 675 to 750..(If memory serves right)

[Alan Wheeler]

Hmmm, nver heard of that way before CSY. So how do you determin the speed with the strobe?
There is a Perkins V8. In fact there are three maybe four models of the engine. Hence why I asked the poster, V8.xxx? The V8 is followed by a . and then three other numbers which determin the model. e.g. V8.510 & V8.540 are two models.
I was hoping the original poster could tell which one, and I could tell him what the proper idle speed would be. I suspect the idle set screw has become loose and has changed position for the most obviosue place to start looking anyway.

[GordMay]

Q. So how do you determin the speed with the strobe?
A. You count - very quickly!

[CSY Man]

Q. So how do you determin the speed with the strobe?

He-he, ya guys are funny.

Well, the strobe is rather to calibrate the tach, then adjust the idle speed.

Many a times it may be off for various reasons..Being powered by the alternator and all.

Aye, did not know about Perkins V8s..

In sailboats around 40 feet one knows very well about the Perkins 4-108, the 154 and the 236..Seen 'em all, especially in the CSY 33s, the 37s and the 44s.

So, uh, how to adjust the idle in a Perkins V8...?

No idea, I thought the guy perhaps meant a 4-108..