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johnpair · 05-01-2009, 20:38

SkiprJohn,
Thanks for the "awakening".
I did ask in another thread about the BMW marine diesel, but got no answer. I guess they are a rare breed. And then, asking about the fuel tanks (while I was at it) sort of changed the subject, a little bit, I mean the 4-108 topic.
Thanks,
J.P.

Kanani · 06-01-2009, 10:27

Quote:

Originally Posted by CarlF

All the above advice is good but I'd first replace anything that would need replacing after four years in any case. If the engine starts, you're ahead of the game and know how to do it in the future. If it doesn't start you've removed most of the obvious problems.

Replace Fuel filter, Oil Filter, Oil, Impeller, Coolant, Battery, Belts, Fuel

It would be best to simply dispose of the fuel - properly. Today's diesel blend is very different from four years ago due to environmental issues. Mixing the two just creates a mystery (I'm assuming you have less than 100 gallons on board)

Remove and clean all electrical connections with a brass wire brush between the battery and starter

Turn the engine by hand to make sure it isn't frozen.

Now is the time to gather female bystanders who can be mightily impressed if it starts and console you if it doesn't. Make sure they know about the macho mechanic things you've already done.

If you didn't pull the injectors (which would be best but is a little risky if you haven't done it before), then crank the engine for 5 seconds with the stop held out. Wait 30 seconds then crank for another 5 seconds in the same way. This will coat the cylinders with oil before it can start.

If by some miracle it does start, try to look like you expected it. Nod to the adoring female bystanders. Then make sure the oil pressure gauge shows pressure. If not, stop the engine. Next, look for coolant water out the stern. If you don't see it within 20 seconds stop the engine and figure out why.

Carl

Kevin,

You've had some good advice. I would agree with this post most.

I would remove the injectors and have them serviced, no matter what. They will install new seals that are more conducive to todays fuels and increase your chances of success with this engine. The injectors should be serviced periodically anyway.

While the injectors are out. I'd do as Carl suggests. I'd also put Marvel Mystery Oil (no...I'm not kidding) in the cylinders before cranking. Watch your face when you crank the engine with the injectors out. Put a rag over the open injector ports.

By all means, replace the W/P impeller before you ever turn the engine over. Even if it looks good, it will probably fail in a short time...do it now, by all means.

After you have her all cleaned up and put back together with new oil and bled fuel system, crank the engine and she should fire right up. If she doesn't fire on the first few revs, spray a quick shot of WD40 in the air intake while turning over the engine. This is guaranteed to fire her up. However, don't continue to spray WD40 in the intake to keep it running. If she dies after firing on the WD40, bleed the lines again. You may have to do this a few times to get all the air out of the lines.

If you have no air in the lines, good compression and freshly serviced injectors, that engine will run.........check to be sure that the kill lever is not activated on the injector pump.

Kanani · 06-01-2009, 10:33

Quote:

Originally Posted by johnpair

Hi all,
I posted this question in an other thread but got no answer yet, so I'll post it again here, since engines are being discussed.
I'm interested in a Lord Nelson 41 1981 with a BMW 3 cyl. 50 HP model D50-2-F-45-150 diesel engine, with approximately four and a half to five thousand hours.
The owner who obviously wants to sell me his boat tells me that although the engine is original, it has been cared for and serviced regularely, and could possibly accumulate well beyond ten thousand hours without a partial/complete rebuild/refit.
I am subjective and would like to believe him. Is this realistic, or pie in the sky...
Also, the boat (which needs some attention in a few areas) seems to be in good shape generally, has the original black iron fuel tanks. Won't they need to be replaced in the not so distant future?
Thank you in advance for your advice.
J.P.

johnpair,

(hijacking this thread aside).........Run the engine and get it warm. Stop the engine and remove a cup of oil. Take the oil and get it analyzed. This will tell you all you need to know about the condition of the engine.

The analysis report will tell you all of the metal particles that are in the oil. They will tell you how that all relates to the wear on the different parts of the engine.

5K hours on that engine should be nothing. You won't know until you get the oil analyzed though. There could be bearing babbitt material in the oil that indicates the engine is due for a complete OH.

johnpair · 06-01-2009, 11:33

Kanani,
Great advice, thank you.
J.P.

DeepFrz · 06-01-2009, 11:53

Yes, it does seem that I left out a few words...<gr>

What I meant to say is that you are much more likely to get good advice if you post properly.

GeoPowers · 06-01-2009, 15:04

I'm surprized with all of the expert advice around here that the first and quite possibly most important steps to take when servicing your own marine engine have been left off:

1. Open up an ice cold beer...

2. Repeat step 1 as required during maintenance and repairs to ensure constant flow...

SkiprJohn · 07-01-2009, 12:09

Aloha Geo,
Those steps were assumed to be general knowledge but every now and again it is good to be reminded. Pop!
Kind regards,
JohnL

Sam Plan B · 07-01-2009, 16:41

Back to the Perkins 4-108. These are great motors. My boat came with a 4-108 and it had been on the hardstand for 5 years. I would say, approach the motor with common sense. Change the oil and oil filter first. Change the fuel filter next. Make sure the fuel tank has been completely full. Add some fuel preservative for good measure. The stuffing box may need repacking but that will take you all of 15 minutes once you actually get your hands on it. Fire it up. Put it in gear at the dock and watch it for a while to see if there is excessive vibration, over heating etc. Check the fuel filter. If its still clean you have a winner.

Kanani · 07-01-2009, 17:02

Quote:

Originally Posted by Sam Plan B

Back to the Perkins 4-108. These are great motors. My boat came with a 4-108 and it had been on the hardstand for 5 years. I would say, approach the motor with common sense. Change the oil and oil filter first. Change the fuel filter next. Make sure the fuel tank has been completely full. Add some fuel preservative for good measure. The stuffing box may need repacking but that will take you all of 15 minutes once you actually get your hands on it. Fire it up. Put it in gear at the dock and watch it for a while to see if there is excessive vibration, over heating etc. Check the fuel filter. If its still clean you have a winner.

He may or may not get away with that. My biggest concern would be the W/P impeller. No way would I crank up a motor that has been sitting that long without changing the impeller. It just isn't worth the risk. A new impeller and cover plate gskt is like $40 and easy to install. It may look good, it may even work for a while. The problem is, there is a strong likelihood that the impeller will fall apart sooner than later (if not immediately). If the rubber falls apart, it ends up in the cooling system somewhere and you are out somewhere with an overheated motor

.

The fuel filter could have condensation and rust in them. Taking a chance on the filters would be down-right irresponsible. I'd clear all of the old fuel out of the lines, at the very least (after changing filters). I don't think that I would be too concerned about the fuel in the tanks. Just suck up a little fuel from the bottom of the tank to see if you have water or rust. If you have water, it can be sucked out with a pump. A fuel additive and new filters will take care of the rest.

Don't be surprised if your injector pump starts leaking. The seals in there are not made for todays fuel (unless the pump was rebuilt in the last 10 years).

Sam Plan B · 07-01-2009, 18:09

That's why is said to fire it up at the dock and see if it overheats etc. As a matter of fact, I had to change my raw water impeller too. One of the blades had broken off. I pulled it out of the hose with a needle nose plier. It took about 20 minutes. I say again, a 4-108 is a good solid reliable piece of machinery. Change what makes sense to change. Test it at the dock. Take short runs to be sure. Then make up a list of normal maintenance tasks to be done on schedule. And do them.

oldcal46skipper · 20-11-2021, 04:57

Mr Perkins built over 500,000 4.108's. Why? They are GOOD! Most of them went into farm or Industrial equipment. If they don't work, the operators children may not get fed!

We have rebuilt over 200 4.108's in the last 15 years, mostly for boats.The primary cause of failure is DIRTY fuel or water in the fuel system. If the engine has not been used in the last 12 months, I suggest "Polishing" the fuel. Empty each tank into clean barrels, using a water separator filter and at least a 30 micron filter. Many marinas or boating areas will have fuel polishing services.

While your tank(s) are empty, add a commercial fuel tank cleaner and the appropriate cleaning fluid. Read the instructions! After allowing the fuel that was pumped out to set, per instructions, then pump back into the cleaned tank, with the appropriate amount of "Cetane Booster"

Step 2 is back flush your system starting at the mail line entering the high pressure pump, loosen the next fitting, ( maybe the low pressure mechanical or electrical fuel transfer pump) or the final filter. Move your attachment, I use a 12 volt fuel transfer pump. To the next fitting, mechanical transfer pump or final filter. Then pump clean fuel back into your "Day" tank or final tank while observing flow.

Step 3 Assure all fittings are tight and follow engine builders instructions for bleeding air from the system, Test by using your engine starter, but not too long as it can overheat. Be sure you have a reliable person near the fuel shut off & engine KILL switch, as you are bleeding at full throttle on most engines. Sometimes they will start at full throttle so have your helper ready to close the throttle.

Assure you have the engine lube oil topped off& clean filters and look for lube oil, coolant and fuel leaks. Don't "Over Prop" like having your truck in high gear while climbing a steep hill. Michigan Wheel has a very good application matching boat size, WLL, beam, load, HP, etc suggested prop size.

You may obtain over 10,000 hours usage before rebuild. The "Average" private boat owner in the USA, uses his boat 97 hours each year.

LittleWing77 · 20-11-2021, 05:29

OldCal,

This is a thread from 2009...

Hopefully the OP has got that Perkins sorted and running by now!

LW77

marcjsmith · 05-12-2021, 06:02

Old cal, don’t fret, I did the same thing, only I send the op a pm about how I got my 4108 Un struck and running after sitting in the hard for almost 9 years

Doh

coopec43 · 06-12-2021, 04:56

Kevin

You may not be aware that Perkins never produced a marinised version of the 4-108. They supplied basic engines to jobbers who marinised them in to their own design. You might pick out a few different versions here:

https://www.google.com/search?q=Mari...&bih=574&dpr=1

But what the guys are saying above is still good advice.

Replacing hoses can be a real problem as they, in all probability are not, genuine part numbers.