6BT 210hp RPMs increasing on their own

[Gary Marshall]

Hi all,

My partner Allan had his 6BT rebuilt recently and has been using it about 2 weeks now, prob put on about 100-150 hours since the rebuild.

Just yesterday the rpms in idle started increasing on their own. He thought it was the cable, but disconnected the control cable and the same thing happened. He can use the idle screw to bring them back down, but then when he restarts the engine, often the rpms are too low. He is using a “new” re-manufactured fuel pump, so we assume that is the issue. 

Just thought I would throw it out here to see if anyone had any suggestions on what to check.

p.s. I actually have to order for him the pick up for the tachometer, as that had stopped working, so we don’t know the actual rpms, but it is very clear when the engine revs pickup on their own.

Gary

 

 

Topic

[Gary Marshall]

Thanks. It is good to have that specific knowledge just in case he needs to get the pump done. 

As mentioned, it’s Barbados, so there are not a huge lot of options in terms of shops that do this sort of thing. Don’t know too much about this particular person. Good to know that the price is fair. Labour tends to be cheaper here, relative to the US, whereas imported parts would cost quite a bit more. 

He did go fishing yesterday for 10 hours or so, and didn’t mention any issues on it yesterday evening (I had forgotten to ask about it)

Thanks all.

 

[Francis Valerio]

Gary $750 is a good price to get that pump rebuilt.  Obviously as long as it is a good shop that knows how to do it the right way.  I paid about the same at one shop about 5 years ago but then paid more than double that at a local shop 2 yrs ago….

both shops did good work so that is the main thing.

 

Like Tony says this is in the Governor linkage area inside the pump.  Absolutely is fuel related whether it be contaminants or the lack of lubricity of Ultra Low Sulpher Diesel…

I do wish your friend luck

1 user thanked author for this post.

Gary Marshall

[Tony Athens]

I have personally experienced this exact issue twice.. Both times were related to “low sulfur fuel”  low lubricity”.. The governor linkage in the pump needed to be opened up to  the high of the tolerance spec. Nothing to do with the injectors.    

1 user thanked author for this post.

Gary Marshall

[Gary Marshall]

I asked him for an update yesterday and he said the issue reoccured twice since then, but to a lesser extent. It did clearly make a big difference, but it might still not be 100% resolved.

He got a local quote for USD $750 to rebuilt the pump, but the person also wants to clean the injectors also. Might all seem logical, but keep in mind that these injectors were all cleaned recently while the engine was rebuilt, and this is a “new” rebuilt fuel pump he is using. So, he will continue to see how it goes for now. He is a commercial fisherman so the boat gets practically daily use.

G.

[Francis Valerio]

Gary

That is great news.  Always important to follow up on the post.  Future people will search these posts that can help them.

Hopefully she keeps running good

 

Frank V

[Gary Marshall]

Guess what?!? This solution seems to have worked. My buddy tried it at first a bit, and it didnt’ seem to make a difference. Then he took the boat around to the other side of our island (Barbados) to a sheltered port, and added more ATF (I think filled the racor with it), and the problem resolved. He has used the boat a bit since and the problem has not re-occured. So, fingers crossed I guess. Thanks again!

[Francis Valerio]

Hi Gary

That engine uses a Lucas-Cav injetor pump.  My thoughts are this is an issue with the pump.  Cav pumps when working properly are good pumps but can be finicky to put it mildly.

They do not tolerate water or any contamination in the fuel.  No diesel fuel system does but the Cav pump is worse for this.

The internal mechanisms inside the pump cover get rusty pretty easily and this can affect the governor and the springs that attached to the various mechanisms that are inside of the pump.

You could try running some ATF through the pump via the fuel inlet line or fill the secondary fuel filter up with straight ATF and this “may” help.  In my opinion this will not hurt anything and I have done it myself in the past. 

The 6BT 210 is an old school engine with an old school injector pump so old school tactics can sometimes work

 

 

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Gary Marshall

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