timber jack 353 won't start air in injector

rockwall · December 14, 2021, 06:51:50 AM

My friend has a Timberjack skidder with a 353, he was coming out of the woods two winters ago and the skidder lost power and quit. He wrapped it up for the winter and finally got back to it. We discovered the emergency stop was tripped,closing off air to the blower and the inlet fuel line to the injectors was blown off. We drained the fuel tank, put in clean fuel , cleaned emergency shut off, put fuel line back on, checked the fuel filter and got fuel up to injectors by turning engine over and bleeding air. We could not get one injector air free, air just kept pissing out. So after many tries, new batteries, good connections, recharging batteries, bleeding air, a little ether, it still just spins over and won't start. (Air in injector closest to skidder operator.) Any help would be greatly appreciated.

kiko · December 14, 2021, 06:03:08 PM

The injectors tip is likely damaged and compression is pushing the air back in the line.

grabber green · December 14, 2021, 06:58:35 PM

Don't worry about bleeding those injector lines . They dont work the same as most popular 4 stroke diesels with an actual timed injector pump . Take off your fuel return line and see if your getting fuel there.Make sure the restricker fitting on the return line isn't plugged. If that checks out look at the rack and make sure the injectors are opening. Also you might want to check the pump pressure, it's really low pressure (15psi at low idle to 60 or 70 psi at max rpm) compared to 4 stroke diesels . Will it not even hit on either? Also if it was running with that emergency shut off closed it probably sucked the seals out of the blower.
Should still start though.

krusty · December 16, 2021, 09:49:19 AM

53 series service manuals are easy to find online. There is a section of fuel flow test on the return line you will need to do. There is no need to bleed the injector lines as they are self bleeding injectors. My guess is you need a new fuel pump. Cheap and easy fix.

bushmechanic · December 20, 2021, 05:58:26 AM

Seems strange that air is only coming out of one injector, maybe you have a bad jumper line. Put a can of fuel up over the engine to get it running, gravity flow to the filter housing. This will eliminate any bad lines coming from the fuel tank and help get it running. Any 90 degree fittings in those engines are a source for debris to hold up and stop fuel flow, check those. The fuel pump drive is also an issue as it's a small square tube and wears out, the early ones were really thin but later models had a thicker walled one with no issues.

mike_belben · December 20, 2021, 11:05:56 AM

I own a 2stroke detroit and know nothing about it because the old turd always runs. But i should probably learn how this system works. Anyone got any good links?

C5C Tree Farmer · December 22, 2021, 11:44:13 AM

There is a good chance that the fuel line to head got blown off by compression pressure leaking past an injector pintle valve. This would have also blown all the fuel out of the head rails and depending on the engine rpm when it happened may have scored all 3 injector plungers because of the lack of fuel for lubrication. The best course of action would be to remove all 3 injectors and bench test them for a spray pattern. It's easy to do.
Mount the removed injector in a soft jawed vise and fill the jumper line ports up with WD-40. Tap the spring loaded plunger with a brass hammer and watch the fuel delivery. It usually falls into 1 of 3 categories:
1. A chirping sound is heard accompanied with a fine mist fuel delivery. Injector is OK.
2. A single "pop" sound accompanied a stream type delivery. Replace.
3. The WD-40 runs out the tip of the injector by itself without plunger movement. Replace.

BargeMonkey · December 22, 2021, 10:36:26 PM

Quote from: mike_belben on December 20, 2021, 11:05:56 AM
I own a 2stroke detroit and know nothing about it because the old turd always runs. But i should probably learn how this system works. Anyone got any good links?

Mike I can help you get ALL the 2 stroke knowledge you want, it just comes in 2-6wk doses... 🤦‍♂️😆

BargeMonkey · December 22, 2021, 10:39:29 PM

Buddy how far into this engine are you ? What have you done / not done so far ? Valve covers off and you've confirmed you don't have other issues ? I've got a BAD story that sounds just like your where you think it's something stupid, engines just magically dies 🤷‍♂️ and the cam gear let's go. Why I'm wondering how far your actually into this. It's a Detroit, fairly simple.
I'm trying to fit these into my 353 for more power 😆 same injector just a touch bigger.