Prevenative Maintaince

[Hi Ho]

I read with interest a previous post where Richhh suggested that running a deisel engine with a mixture of 75% marvel mystery oil and 25% engine oil was a good way to remove any carbon build up. I have a 1977 12hp Farrymann that starts and runs fine but seems to smoke more than I like especialy at ideal [ more than some others] I have never had any deposit on the hull around the exhaust so maybe I'm asking for too much. I had the injector rebuilt which helped but still I have more black smoke than I like. The boat is new to me so I don't know what kind of use or maintaince the engine saw from the previous owner. We operate the boat on Lake Erie it does not have a closed system and even after changing the thermostat I can not get the engine up to operating temp. Because of all that I read I fear my engine is certainly not being operated as it should be and could face an early demise. Some seem to think with the boats large exhaust [1.5"] and it's single cylinder and low operating temp that it's operating just fine and I should just run it and not worry. So my question is should I give the engine a treatment has Richhh suggestes as a prevenative measure, what's the risk, or should I leave well enough alone. I would like to keep the yellow piece of iron running as it really is one simple engine.

[never monday]

I'd leave it alone and get off of the marina "red" fuel and over to street diesel. The red will cause an increase in smoke production due to the slightly higher sulpher content.

[JGI417]

I agree think using a mixture of 75% would cause more of a problem than it would help, what oil are you running in the engine now

[Hi Ho]

Farymann recommends 20Wt so that's what I use. In another post Richhh was suggesting that a mixture of 75% Marvel Mystery oil and 25% of regular motor oil, then run at idle for 1 hr. let the engine set for one week then repeat the idle time and then change oil with your regular weight oil. The purpose of the excercise is to remove any carbon on the cylinder wall and rings to improve compression. My thought was since the engine runs so cold and has mostly idle time on the engine that maybe this would be good to remove any carbon etc. I also wonder if it would be worth my while to install a heat exchanger [closed system] in an attempt to get the operating temp. up. Where I dock I only run the engine about a 1/4 of mile to get to the lake with a drawbridge in the middle with lots of idling time waiting for the bridge to go up. I usually run the engine for maybe 5 minutes in the lake at hull speed. I know where the previous owner docked and his operation probably was about the same, just to much idling time in my mind with thoughts of a pemature death. My other personel fault is I have a tendency to try to fix things that are not broken, a compulsive tinkerer!

[never monday]

FIrst and foremost you need to run that puppy under load regularly for atleast an hour. Secondly the 15W is cheap to rebuild if necessary, so if it ain't broke, don't fix it.

[Hi Ho]

Thanks Never Monday
I'll just switch fuel and just run it! The dam thing is just so simple compared to a gas engine I feel like I need to do more than oil changes etc. Just my compulsive prevenative maintance impulse.

[Richhh]

I agree with NeverMonday and add one comment. Diesel Fuel has a short shelf life and then rapidly decomposes, marina fuel sits around for a long time. Old fuel has a lot of the 'lighter fractions' simply go out the vent and the 'heavier fractions' slowly form into a goo that doesnt burn well. These 'goos' simply go through the combustion chamber as liquids only to form deposits as 'coke' in the exhaust manifold and injection nozzle (yielding a higher than normal back pressure).

Simply empty the tank of old fuel (clean out / scrub the insides of the tank if you havent do so in the last 5 years), take the old fuel home and use it in your oil burner, and replace with NEW fuel purchased from a high turnover 'truck stop' ... fresh fuel. Then see what happens. You might also consider to add a cetane booster as the old Farryman was built for a fuel that had a higher cetane number than is currently available today.
.... and worst of all, marinas usually charge much much more for this old/decomposed stuff than the 'taxed' & fresh fuel you get at a high turnover 'truckstop'.

If you have lower than normal compression or a high leak rate during a leak down test, then you can try the MMO soak to usually good effect.

Change to 'good' fuel first and see what happens.

Reference for fuel storage and shelf-life, etc.: http://www.bp.com.au/fuelnews/ADF1402.pdf

[Alan Wheeler]

As Pat has said, run it hard.
Why do you have a low engine temp? Do you have a thermostate? You should!. Or you should reduce some of the cooling water flow to allow the engine to warm up more. An engine running too cold could cause all sorts of problems.
NEVER "water down" an oil. Especially in many diesels that have a single weight oil specified. Like an SAE 20 or 30.
The other point, you won't get a premature "failure". It will just get tireder and tireder and smoke more blueish smoke. These engines will very rarely just stop.

And lastly, you have to be very careful on engines that are very old in hrs, especially petrol engines, that if you give an engine a good clean with an oil flushing product, you can actually cause it to start burning oil. The best method of cleaning is a good hard run, then a fresh oil change.

[Hi Ho]

Thanks for all the replys! Alan I've replaced the thermastat but still can't get the engine temp up[about 100%] the engine does not have a heat exchanger it is fresh water cooled. Even running it fro several hours at hull speed with lake temps in the 70% range all I can get is about 100% engine temp.

[DeepFrz]

HiHo, are you sure that you have the correct thermostat installed? Have you checked it against the service manual? I'm not implying anything here, but it's easy to replace a thermostat thinking that the one installed is correct only to find that the PO or a mechanic had replaced it with the wrong one.


Phil

[CaptainK]

Hi Ho.

How's your water pump?

Is it clogged up?

Are any of the water hoses clogged?

You could start looking from there?

[Rod Headlee]

Is your engine raw water cooled? You said you have no heat exchanger. If it's raw water cooled, you don't necessarily want to bring the temp up. Sure it's better for engine performance, but you run the risk of breaking something if you suck cool water into an engine that's heated up to 180* In other words, if you run the engine until it reaches proper operating temp, around 180*, then shut it off and restart in a few minutes without letting it cool down, sucking in 70* lake water, you could crack a head or cylinder where the waterjackets pass nearby.

[BC Mike]

A raw water cooled motor may only be required to run at about 160F maximum. The engine block surface temperature of my Yanmar is 125 to 140F. Too hot and the salt gets cooked out of the water and it sits inside the engine.
Michael

[Alan Wheeler]

Rod, that's what the thermostat is supposed to stop. It should only open when it gets hot enough.

Although, it is normal for a raw water cooling system to run much colder than normal. This is not so much a salt issue, but a pressure issue, flow and intake temp issue. An engine can be allowed to run at a much higher temp, because the enclosed system is under pressure, like 13PSI. A raw water system doesn't usually create that sort of pressure, so the system is made to run cooler.
Plus it has a continuose supply of very cold water, instead of having a seperate closed circuit heated system.

[Hi Ho]

It is RAW WATER cooled, I was using the term FRESH water to try to indicate that the boat is operated in fresh water so I don't have the issues associated with salt water. When I replaced the thermastat in checking with the parts/Dealer to assure that I had the right stat and was telling him my problem he did'nt think I had a problem. He did'nt think that I would ever get the engine temp up given the operating conditions and did'nt surprise him and it was normal. Given that the engine has been operated in this enviroment for 28 years and the slight smoking I'm experincing is what prompted my first post with doing a one time engine de-gunk/carbon deposit treatment. I asked the question for fear that I might be taking a risk with this flushing when l might be better off leaving well enough alone. I'm now of the opionion that I will let her run, run her hard and when she starts to use oil, starts hard etc. then will just to a rebuild. Thanks for all the good advise.