Perkins with No Power

[Seahunter]

One off the problems I've seen is a plugged AIR intake as well as the water intake. It causes white smoke cause the fuel pump to run rich, heat up under load and bog. If the engines been sitting there could even be something living in there, but usually the screen is just plugged up with oily dirt.

[DeepFrz]

Or a partially plugged exhaust mixer elbow.

[Seahunter]

Originally Posted by DeepFrz

Or a partially plugged exhaust mixer elbow.

Yeah, that too.

[Chief Engineer]

Is it white smoke or steam?

[Chief Engineer]

Is there a water heater plumbed into the fresh water side?

[Chief Engineer]

And what do you mean about severely adjusting the idle?

[Mark Zarley]

The Chief brings up a valad point. It you have a hot water heat exchanger that is partially plugged, it will give you very hot water at the kitchen tap. And produce steam at your exhaust. If you have a restricted air intake, you will have a sooty or black exhaust ( incomplete burn) just like a fouled prop. If you need to rod out your engine heat exchanger ( restricted flow) or have a restricted exhaust mixer elbow, any of the above will cause your problem. IS THE EXHAUST HOSE TO HOT TO TOUCH BETWEEN THE MIXER ELBOW AND THE NEW MUFFLER WHEN THE ENG OVERHEATS? If you can hold onto it without discomfort , the raw water system is probably OK. Would then concetrate on the fresh water side of the eng.

[billwa]

Overheating aside, if you are successfully increasing engine RPM without increasing boat speed, your prop is incorrectly sized and is slipping - or alternatively your transmission is slipping.

I suggest you may have an undersized prop, or you have a blown/overheating transmission.

[Minggat]

I have the same problem. At the moment I am not in the same country as my boat so nothing I can do.

Been down the expensive road trying to get past it. What I failed to do was the exhaust system. When the problem first showed up I was able to get all power for one run, and then could not repeat it the next time. Then I got it back again. Now, it's just low power all the time.

Speaking to one Perkins mechanic (and I've spoken to several) I was told that he had seen exhaust hosed that you'd have no idea had a problem, but were choked off by loose rubber. At one point I have had the exhaust hose kinked for some weeks while doing other work. I'm thinking that maybe I compormised the hose lining and now it hates me.

So when I do get back to my boat, it will be the exhaust elbow and hoses.

[SkiprJohn]

Billwa was close. The first thing I check when a Perkins overheats is whether or not the prop size has changed. I don't agree that it might be undersized. I would think it would be oversized. If you can run it up to good speed at the dock in neutral with no overheating then you know it must be something in the drive train that is holding you back and making you overheat at load.
kind regards,

[billwa]

The perkins should be geared and propped to cruise at 2000 rpm, which is where it develops its peak torque.

If at 1500-2000 rpm you are only achieving 2 kts, either:

a) you arent turning the prop at the designed speed (transmission problem)

b)the prop is incorrectly designed for the installation.

At 2000 rpm you should should have a boat speed of 5 kts or so in the ketch you have if it is correctly propped and the tranny is transferring the power to the prop.

[ivndrago]

All, I have rechecked all connections (new hoses are without kinks and in good condition). I started the engine again yesterday and as expected, it started right up without hesitation. The (raw) cooling water flowed effortlessly but I did forget to collect the waterflow per minute suggestion from donradcliffe. We did check the prop and it turns easiely while in neutral as suggested by slacker; not sure what brand the tranny is.
I am avoiding a repower as I believe its fixable. Just need to figure it out....Unless it blows, I will continue trying.
I did try to see how high it would rev and could not make it past 2000 RPMs....I even tried manually revving without success....
...and the beat goes on!

[Jesse]

I share Chiefs interest in the severely adjusted throttle. That seems a bit odd, could you elaborate on that?

[SkiprJohn]

Its really hard to troubleshoot from a distance.
From what you've said: You cannot make the engine go above 2000 rpm whether in neutral or in gear. Correct?
Any weird noises between the engine and transmission?
When shifting between neutral and forward or reverse does the engine really lug down?
When you said you tried increasing rpm manually is that at the fuel injection pump with the throttle control cable disconnected?
So many variables.
Kind regards,

[ivndrago]

Jesse, The mechanic had to increase idle speak to like 1200 just to get her started. After rebuilding injectors, we lowered the idle speed down to 750.
SkiprJohn, Yes, cannot get engine above 2000 in neutral nor gear. The engine runs great. For what it is (Diesel), it runs fairly quiet. When going between one or the other, the engine behaves normally.

When we installed the new muffler, we did not look at the mixer elbow. I will look into that.

The boat does have a water heather but I have not checked to see how the water is running. I will look into that.

I will also check the exhaust hose between the mixer and the muffler.

I am thinking that replacing hte Heat Exchanger may be an alternative....thoughts?

Oh BTW, I do appreciate everyones help and ideas with my problem.

Thanks.