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Old 20-02-2014, 10:32   #106
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Re: 50hp Perkins won't rev past 1900rpm

http://www.tb-training.co.uk/CIsys.htm

The above is a long article with a very good description of fuel injection pumps on Compression Ignition (C. I.) engine; also know as a Diesel engine. This is a well written article describing various types of fuel injection pumps. Look for the D.P.A. type of fuel injection pump with hydraulic governor, as this is what is on the Perkins. This pump with the hydraulic governor has an intermediate transfer pump that varies some in pressure depending on engine speed. That pressure is balanced against a spring and a piston and that is how the engine speed is regulated for a given RPM setting. My thinking is that if the piston gets mucked up with dirt and/or water, the governor is going to fail at keeping the engine speed constant, either too high as in a run away engine or to low an RPM as you are having, the piston is going to stick one way or the other depending in the dirt/water location in the piston’s cylinder. What is usually needed is an injection pump rebuild unless you are really handy with tools. Be sure to wash everything down with carburetor cleaner and be very careful about dirt. There are rebuild kits available.

By the way, here is another thing to consider. Water in diesel will flash to steam in the cylinder and the steam scours the lube oil off the cylinder walls. This creates a rust problem with the cylinder walls and the rings. The engine can seize and you will have to pull the head and use penetrating oil to free the rings with a block of wood and hammer to perhaps knock the piston loose. If you pull the starter, you might be able to loosen the piston by prying on the starter ring teeth after putting some penetrating oil down the fuel injector holes, but probably not. If you try prying on the front pulley, be careful as you could break the woodruff key that ties the pulley to the crankshaft. And finally, clean the muck and water out of the diesel tank, or your injection pump and/or engine could malfunction again.
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Old 20-02-2014, 11:58   #107
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Re: 50hp Perkins won't rev past 1900rpm

We all know a diesel engine needs lubricating oil, coolant, air and diesel fuel in measured quantities.
I know a guy who used a rubber hose to route his engine air intake away from the engine and fitted a paper element air cleaner to reduce noise, it was surprising how much fine dust is collected on the paper element air cleaner.
His engine began to suffer a similar problem, once he tried increasing revs the engine seemed to be holding back from revving freely, he also cleaned his fuel system meticulously.
The problem eventually turned out to be the engine air cleaner hose was delaminating, at slow speeds the engine ran fine but once he increased revs to hose was collapsing inwards preventing the engine reaching full revs.
Always try the simple way first, check the engine can breathe freely before spending megabucks unnecessarily.
I hope this helps someone somewhere.
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Old 20-02-2014, 11:59   #108
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Re: 50hp Perkins won't rev past 1900rpm

Quote:
Originally Posted by lancelot9898 View Post
I'm not sure how much cranking it takes to back water into the cylinders, but if you're pumping saltwater through your heat exchanger without getting it to start then there is not enough pressure to allow the water to exit from the exhaust so consequently the the water will back into the cylinders. It's the exhaust gases that allow the water to exit and without start up there are no gases.
With an Albin AD2 it doesn't take much cranking to get the water coming back up the exhaust. Each engine and exhaust system is a bit different so its hard to say with his engine how much cranking.

I can't offer any more suggestions. He's got one cylinder that probably needs injector work. He says he has topped off batteries so it must be spinning fast enough. I'm assuming there is unobstructed air going into the intake. If the silicon spray or WD40 into the intake without the aircleaner doesn't make it fire then something more serious is going on.

Good luck and let us know how it works out.
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Old 20-02-2014, 17:09   #109
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Re: 50hp Perkins won't rev past 1900rpm

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Originally Posted by forsailbyowner View Post
Heres the thread where I went thru similiar issues trying to get started. It all ended when i used silicone spray into the intake while cranking. If you havent yet, give it a try. its the silicone lubricant spray you see on the shelves in auto parts stores and other places. You should get the engine firing at least while spraying even with air in lines bad injector pump or whatever. It worked for me.

Another Bleeding Dilemna 4.108
OK. Will soon be heading down to supercheap to get me some silicon spray and am definately closing my water intake when I crank it next time. Fingers crossed.
Westwind.. I will have a good look at that link. Thanks.
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Old 20-02-2014, 17:11   #110
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Re: 50hp Perkins won't rev past 1900rpm

Forgot to ask. Can anyone steer me to the correct can of silicon spray? What is it usually sold as?
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Old 20-02-2014, 18:00   #111
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Forget starting the engine with spray.

Pull your valve cover, check valve play, spin the engine and watch the rocker assembly, have cooling water valve "ON", make sure injectors and pump are properly bled.

Fuel, compression, air and proper timing and that Perkins should run.
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Old 20-02-2014, 18:33   #112
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Re: 50hp Perkins won't rev past 1900rpm

Ok. Covering all my options. Is this the stuff.

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Old 20-02-2014, 18:34   #113
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Re: 50hp Perkins won't rev past 1900rpm

Ydgh

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Old 20-02-2014, 19:41   #114
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Re: 50hp Perkins won't rev past 1900rpm

The easy glide looks like appropriate. If you use the starting fluid remember just a quick shot while the engine is turning over quickly and if equipped with glo plugs dont do it.
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Old 20-02-2014, 19:43   #115
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Re: 50hp Perkins won't rev past 1900rpm

Just remember that starting it with any type of spray does not solve the problem.
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Old 20-02-2014, 19:52   #116
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Re: 50hp Perkins won't rev past 1900rpm

[QUOTE=Cap Erict3;1473110]have cooling water valve "ON"/QUOTE]


this is bad info imho should be disregarded. Just dont run engine for but a moment after starting and running. Then kill and start again with raw water seacock open. Dont know why this would even be recommended? Maybe worried about impeller? If so remove cover and squirt some dish soap in there. Pumping water into a no start engines exhaust is just plain bad mojo and asking for trouble.
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Old 20-02-2014, 19:58   #117
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Re: 50hp Perkins won't rev past 1900rpm

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Originally Posted by boatpoker View Post
Just remember that starting it with any type of spray does not solve the problem.

But will start an engine with a lot of hours that has had air in fuel system.
after doing this my engine ran fine on subsequent starts. Maybe it didnt fix anything mechanical but has worked for me on several occasions after bleeding and having start problems.
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Old 20-02-2014, 20:25   #118
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Re: 50hp Perkins won't rev past 1900rpm

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Originally Posted by forsailbyowner View Post
The easy glide looks like appropriate. If you use the starting fluid remember just a quick shot while the engine is turning over quickly and if equipped with glo plugs dont do it.
I have glow plugs and am about to try it. I need a quick answer. Can I or can't I?

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Old 20-02-2014, 20:25   #119
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Re: 50hp Perkins won't rev past 1900rpm

Orshould I start it without the plugs and use the spray?

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Old 20-02-2014, 20:28   #120
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Re: 50hp Perkins won't rev past 1900rpm

Forsailbyowner. Did you use your glow plugs with the spray

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