Runaway Perkins 4-108 - Now What ?

[Bella Sera]

Have a mid-90's Perkins 4-108 with 2600 hours, always started and ran fine until 2 days ago, when we had a runaway about 15 minutes after startup (went to WOT all by itself, great plumes of white smoke, no response to throttle or shutdown handle). Problem appears to be fuel in the oil (symptom I didn't pick up on was oil pressure had progressively dropped from 55lbs to 40lbs over past two weeks. On the other hand, fuel leaking in apparently equalled oil leaking/burning out since the oil level stayed pretty constant). After incident I checked oil level and it was at least 1 qt over.
1. Changed oil: pulled almost 2 gallons out when just over 1 gallon is normal!
2. Have capped off the pre-heat fuel line (since we never use it) and changed the lift pump to eliminate those as sources of the leak.....but while I can get the fuel filter and injector pump to bleed, cannot get any fuel to bleed through the air vent on the governor.

Should I try and bleed the injectors (by cranking the engine) and see what happens hoping for the best, or should I assume the inability to bleed the governor means the leak is at the injector pump and go through the process of rebuilding that? And still have no idea if we trashed anything internal to the engine.

Any suggesting of a good Perkins guru in the Carolina Beach, NC area? We want to keep heading south, getting cold here!

Regards

[Hannah on 'Rita T']

Bob, when our Perkins races, it is always a clogged fuel filter. So your problems are way beyond me, but once again I recommend Deaton's in Oriental, NC, they have a good engine guy. We are here until Wednesday, then heading off shore to the Virgins.

[Chief Engineer]

Runaways seldom happen in 4 stroke engines/

look at linkage

[boasun]

One possibility is the Govenor... You may want to have it bench tested for worn parts.

[donradcliffe]

The next step is to pull the HP injector pump and have it rebuilt--they will put in new seals and test the governor, especially if you give them your symptoms.

[jannpage]

Hello. Perhaps the clue is the oil pressure. It was dropping before the runaway. Why? dilution of the oil with diesel fuel. Perhaps not running it hard enough get hot and thus burn all the fuel off. Of perhaps a leaking diaphram in the fuel pump. The second clue was the failure to shut down. Most shut down system are independent of the throttle and governor and shut off the fuel. In any case I would guess the runnaway was the engine buning the fuel in the oil that because by now your crankcase was overful and blowing by the rings. Remember on a diesel their is always plenty of air to bun anything that will ignite from compression. Deaton's are good. But first I would change oil. Perhaps check the fuel pump diaphram (It would not hurt to have a spare one on board anyway) and check the oil often till I was sure I was not pump fuel into the oil. NOther ing wrong with checking the linkages are intact and the start/stop soleniod is working correctly. MOstly any even half trained engine man should be able to do that in 5 minutes or less.

[Bella Sera]

Thanks for the responses. In hindsight, decreased oil pressure should have been my big clue oil was getting diluted by fuel leaking in (my original thinking on the oil pressure was I had an oil pump failing or blockage...the added 3 quarts in the crankcase after the problem is sure sign fuel was leaking in). I had ruled out the pre-heater leaking fuel as a cause since that would sit in the cylinders and would have resulted in sluggish start from hydrolock, which didn't happen. But capped it anyhow since we don't generally use it. I did change oil and filter, and put on new lift pump. Throttle and shutoff both go the governor through mechanical linkages and appear to be operating correctly (moving them moves the controls on the governor); don't see how their failure, or an air leak, or clogged filter could account for the extra fluid in the crankcase so I'm ruling them out. My confusion right now comes from the inability to bleed the hydraulic governor, and I'm guessing it's because we've blown the seal between the injector pump and the block, so I'm probably putting more fuel into the oil every time I prime while trying to bleed it? (sigh....another oil change!). So think Don and boasun have it right for next step.

Anyone have recommendations for a good local injection system guy in the Carolina Beach NC area where I could get injector pump/governor bench tested/rebuilt, or should I just ship it to TAD, Foley's, etc? I'd also probably like to have someone competent reinstall it since I'm not positive I can get the timing etc set right......

[donradcliffe]

Dont know where the best injector shop is in NC, but someone should. The 4108 injector pump will have you cursing British engineering by the time you get it out--you will need to make a special tool to get the cap screw behind the pump out. Mark the base of the pump before you loosen it up to get the timing right on reassembly.

[Bloodhound]

The nut on the stud at the back of the IP is a right royal bitch to loosen and/or tighten even on a tractor where you can see everything. In an engine compartment (they are rarely "rooms" on sailboats) it probably will require you to buy a ring wrench and specially bend and twist it to reach the nut. If you punch mate-marks on IP flange and engine block though, it won't be hard to reinstall with correct timing.

[NCboatrx]

Bob,
I suggest that you contact Josh at Specialised Mechanical Services. He is based in Wilmington and runs a mobile service. He does excellent work and his phone number is 910 620 3212.
Stanley

[foggysail]

Originally Posted by Chief Engineer

Runaways seldom happen in 4 stroke engines/

look at linkage

Seldom, but it does happen! My first year of sailing I had a runaway after changing the oil. My guess is I overfilled it. Anyway, when it happened to me, I quickly engaged the transmission and let the engine run its course powering the boat. Fuel shutdown did not work. The boat was enough load to prevent the engine from over rev'ing.

I saw another runaway in a diesel generator that was powering military equipment under design. That particular engine destroyed itself.

Foggy

[hellosailor]

Bella, I don't know that engine but throw this out fwiw:
If you have a mechanically driven diaphragm-type fuel pump on the engine? Usuaully it is simple to pull the unit and check the diaphragm for tears. If that is torn, it needs to be replaced and that could be all it takes to solve the fuel&oil mystery.
Also way cheaper than any other problem and solution, so it might be worth taking a fast look. While that diaphragm is out--if it is old or worn, think about replacing it anyway.

[Bella Sera]

Originally Posted by donradcliffe

Dont know where the best injector shop is in NC, but someone should. The 4108 injector pump will have you cursing British engineering by the time you get it out--you will need to make a special tool to get the cap screw behind the pump out. Mark the base of the pump before you loosen it up to get the timing right on reassembly.

Don and Bloodhound, absolutely correct about cursing the engineering....but mostly about getting the heat exchanger off just to get at the fuel pump.....(this is a "new" 108 with the HE along the side, not across the front....no chance of getting IP out with the HE in place....plus gives us an excuse to pull all the old impeller bits out). Once that was done, removing the pump didn't take so long. As expected, found fuel on the engine side of the IP; seal shot. Hopefully back running by end of week.

[Dhillen]

Diesel engines work on a mix of fuel and air ignited by compression, as we all know. Remove any one of the three and it shuts down. If you can't stop the fuel flow - stop the air intake with a flat board. Don't use your hand! Starving the process of air will stop the engine.
So I have been told but haven't had it happen to me, yet. Anyone done this before successfully?
Dhillen

[SkiprJohn]

I've air starved a Volvo with my rubber slipper. It wasn't a runaway, it just didn't want to stop running. If it was a runaway it would have sucked my slipper in the intake and probably kept on going. I recommend a flat board over the intake or smother it with a heavy raincoat over your air filter. It can't run without air.

kind regards,