Perkins 4236 Won't Fire Up

[plottie]

Thanks to all who have posted similar problems on the forum - we have worked through them and still no success.

Yesterday filthy fuel was sucked in and so primary filters have been replaced. She then ran like a dream for 4-5 hrs as we motored off into the sunset... We anchored up and this morning it won't fire.

Clean, air-free fuel is now being delivered into the Injector pump. We checked, more than once, all the way through.
We have bled the IP and cranked with a cracked injector nut and can not get fuel past the IP. We've opened the cover and checked the crank is turning over and have now run out of ideas.

Can anyone please help - we wanna go sailing!

[Hannah on 'Rita T']

Until the captain gets up to chime in, my guess is there is something in the fuel line between the pump and the injectors. Have you bled all four injectors, cranking until fuel comes out of each injector?

[Blue Stocking]

I know it sound counter-intuitive, but do you bleed the system with the throttle full open.

[Hannah on 'Rita T']

Blue Stocking, we don't. I didn't know which of us your question was directed to.

[Captain Paddy]

I would release all four injector tubes, then crank the engine untill you can see that fuel is spurting from all four. Then tighten them down and the engine should start. If not, I would look at two other potential issues: Mke sure that the injector pump bleed valves on both ends are weeping fuel when you pump the hand pump over on the other side of the engine (after which you may have to do the injector bleed again), or you have a left over blockage in the fuel line, on the tank side of the filters. We took on some crappy fuel in South Caicos last February, and the engine shut down twoor three times because, although the fuel getting through the filters was okay, the crap would jam up the lines north of the filters, usually at the first joint above the fuel tank.

Good luck. The Perkins 4-236 is a great engine and once you track down the problem please post it for our general knowledge.

Cap'n Paddy

[plottie]

Thank you all very much for the help. Good point and yes, we have the throttle on. Cheers for the pointers Capt Paddy we will go through again tomorrow morning (we are on Oz time) as we've exhausted ourselves today, and let you know how it goes.
Neil & Heather

[plottie]

Here's our little update, couldn't get any fuel through the injector nuts at all, plus there is no pressure there if you put your finger over the end. So theory is that the fuel stop mechanism inside the IP may have jammed somehow, as the handle felt a bit wired when we last pulled it...
Engineer had a look, tested the engine fired with autostart spray, and confirmed the problem was in the IP all in 10 mins so our diagnostics saved us a fortune. We are now pulling the IP and injectors off to take for a bench test and service 1st thing tomorrow morning. Neil took some pics as he removed everything so I'll try post them here. We also found an online manual for the IP if anyone is interested?

Thanks again

[Boracay]

My John Deere manual warns against allowing any chance that spray from injectors could get onto the skin.

Apparently it can get under the skin and cause gangrene.

Best to find another way to check.

[SimonV]

Before you go removing the IP there is a filter that is not made readily common knowledge, it is located just inside the fuel inlet pipe in the IP. It is a micro filter and easily lost. It is not even shown on a lot of IP drawings, but is the cause of most injector problems. A lot of expensive IP rebuilds are done when this filter can be just cleaned (some of the time). Try this filter first and if there still is the problem then rebuild.

[Philsboat]

Sometimes the fuel pickup filter in the tank gets plugged with crap floating in the fuel.
Pull the fuel line off and blow it out with compressed air.

Phil

[Captain Paddy]

Good luck, and I'd be most appreciative of any pictures showing the interior of the IP and the procedure you're going through.

Thanks.

Cap'n Paddy

[plottie]

Thanks SimonV, found the filter and it seemed ok, great tip for future maintenance checks though.
Update is the IP is being rebuilt ---$$$ . Diesel engineer pulled it apart and it was filled with rust and gunk from years previous mistreatment, or "the sinking incident" of the last owner. Shouldn't have been working at all. I did ask to see it before we approved the rebuild, it was presented like a specimen on a dissection tray and am cross to not have taken a picture of the tray of parts for you Capt Paddy - was in total shock at having been given the quote for 2 boat bucks to fix it.
Hindsight heroes - we should have pulled the thing apart ourselves, bought a service pack cleaned and put it back together-ish and then taken it to the $$expert to bench test and refine.. Lesson learned, and will post procedure and all the pics we have when we fire up the laptop.
Now on to fixing the Capilano hydraulic helm pump while we wait..
Thanks again all
Heather & Neil

[Kettlewell]

One thing to keep in mind for the future is that the 4.236 engine was used in all sorts of industrial vehicles, including forklifts and even some Land Rovers. Here in the USA you can find most parts through industrial sources. Injection work can often be done at truck or industrial shops for much less than at boat places. Another thing I have found is that a very small air leak at the filter or filter housing on the engine can prevent you getting any sort of serious fuel at the IP, showing up as lack of clean fuel at those bleed screws there. And of course there's also the fuel pump not working.

[Kapena]

I don't know if this applies but...My Perkins M20 needs to crank at a healthy speed before the injection pump builds enough pressure to fire the injectors. It has a rebuilt pump and injectors but takes a charged battery to make things happen. Just a side note for you to consider if the pump is the same type.

[Knowazark]

If that's the case Kapena, perhaps you should look carefully at your starter motor.

The bendix type starters on many Perkins wear the bronze bearings and the armature can end up on a slight angle, bind and not spin freely. This results in a sluggish starter motor that can appear to be due to battery, when really its a starter motor issue. Replacing the bearings before armature damage occurs is a good thing.