Cold Starting Question

I had to go get a pump-out yesterday and had to, of course, fire up Dr. Perky on a 50-degree day. I know cold starts are hard in older diesels. Do it sound like a weak battery when you do it? Struggling to turn the rotating mass? Does the more dense cold are restrict the compression stroke?

Tom-

GonzoF1 said:

I know cold starts are hard in older diesels. Does it sound like a weak battery when you do it?
Tom-

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Interesting you chose today to post this question. It was 51 degrees when I went to start up my engine, not really knowing what to expect. I turned the key, pushed the starter button and in less the one full revolution the engine came to life. It might as well have been 80 degrees as the engine started immediately. (whew!) Cummins 330B

I keep an oil-filled heater in the engine room set to low during the colder months. This keeps a constant temperature of about 65 to 70 in the ER. Also keeps the ER dry. Our 27-year-old Cats are happy .

We keep heat in the engine room in the winter. It keeps the space at about 55 degrees no matter what the outside temperature is. So the Lehmans start as quickly in February as they do in August. The engines have cold start knobs but we have never had to use them.

PS--- with regards to the OP's question, when we have started the engines with a cold engine room, low 40s for example-- there has been no noticeable reduction in the cranking speed of the starters. But the engines took longer to fire and "catch" to the point where they were running smoothly. The longer cranking time and the reluctance of the engines to begin running smoothly right away did not seem particularly "friendly" to the engines or starters so we started using the heater in the winter and have never had a "slow start" since.

A block heater is great if you can set one up.

The other is to use a muti-vis oil despite what some will say.

I had quite a few starts this trip where the engine room was in the 40's and it makes a difference unless you use 4 or 8Ds that are made for cranking and fully charged.

Hmmm... Mine struggled to turn over.

GonzoF1 said:

Hmmm... Mine struggled to turn over.

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Starting battery maybe? Maybe a new battery or increase it's size? A 4D is recommended for the starting battery for our engine. I talked to a local, well respected, mechanic when we bought Hobo. His suggestion, since we were in AK and the PNW, was to use an 8D or equivalent. Even when the engine room was 45 degrees, the engine turned over like it was warmed up. Just a thought.

GonzoF1 said:

Hmmm... Mine struggled to turn over.

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One thing that I suspect makes a big difference in our case is that older GBs like ours have a big combiner relay in the engine room the connects the "house" and "start" batteries together whenever a start button is pushed. I use the quotes because on these GBs any battery can be designated for either purpose (or combined) using the battery selector switch. So prior to our changing the battery system on our boat a few years ago pressing a start button sent the power of two fully charged 8Ds to the starter.

Today they get even more since the two 8Ds have been replaced by six 6vdc golf cart batteries, four in the "house" bank and two in the "start" bank. But the rest of the boat's electrical system is unchanged and the start combiner relay is still there. So now each starter is connected to the equivelent of three fully charged 8Ds whenever its engine's start button is pushed.

If our Lehmans were started by a single, smaller "group" battery line a lot of boats use they may well turn over slowly on a cold day as you experienced with your Perkins.

Someone has to say it. That's not considered cold.

Perkins, so I'm assuming indirect injection. Did the glow plugs come on? Too little might not get enough heat in the pre cups. Too much might draw down the battery.

For reference, my glow relay is only on for maybe 2 seconds even around the freezing mark.

No glo-plugs. It only has a preheater (little heating element that warms a small fuel vapor located it the intake) that creates a warm charge for the first compression stroke or two. TBH, I didn't check to see if it was working.

I do have a combiner switch... Didn't use it. I would probably only use it in an emergency.

Series 31 starter battery only about 1-year old.

I'vestarted my small Mitsu w outside temps near 0F but engine compartment temp a little above freezing.

Using an AGM start battery. The engine has pre chambers and glow plugs. I usually run the glow plugs 7 or 8 seconds but at less that 40 degrees I run the plugs 10 seconds. In any condition I've started the engine it's started just about instantly and cranked smartly.

I took out a glow plug once just to see how it glowed and found it got bright red .. Very hot after 10 seconds.

Of course most of you have large and old engines w reg lead acid batteries. So I imagine your systems must be in excellent condition to work well.

For lackluster performance starting condition, battery connections and length of and size of cables all play a part in the equation. I think the size of the battery is not as important as the ability for the battery to supply high current for brief periods of time. Specially designed "start" batteries are best at that. For an old boat w lead acid batts and a big engine a Trojan start battery in the system may be a minimal investment solution to marginal start performance.

I am certain that it's NOT the battery cables.

I suppose it could be my old direct drive starter. I have brand new a gear reduction starter that is a backup. Maybe now is the time to press it into service.

As stated 50 F is not cold.
How cold was the night before? The engine mass probably wasn't as warm as the ambient temperature.
What weight oil are you using?

I start my Cat at or below 32 deg all the time. Sounds like a low battery to me.

Sd

skipperdude said:

I start my Cat at or below 32 deg all the time. Sounds like a low battery to me.

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Me too....I was wondering when one of you guys "up there" would chime in on this thread.

Or straight SAE 30 weight.

GonzoF1 said:

I am certain that it's NOT the battery cables.

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I had a similar problem a few years ago on my Mainship 30. The cables were fine but the connection at the starter was not. After cleaning up the starter motor connection point & re- attaching the batt cable, she fired right up. (Pretty simple check to make before changing starter motors.) Good luck!

GonzoF1 said:

I am certain that it's NOT the battery cables.

I suppose it could be my old direct drive starter. I have brand new a gear reduction starter that is a backup. Maybe now is the time to press it into service.

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What makes you so certain it's not the battery cables? And how about the connections? How about the negative cable attached to the engine?

"Throwing" parts at a problem in the attempt to correct it is a very inefficient way of troubleshooting.

Monitor the battery voltage (at the battery) when trying to start the engine. Now monitor at the starter and engine ground when trying to start the engine.

I see three possibilities:
1) Battery doesn't have the necessary capacity to start the engine.
2) A voltage drop between the battery and the engine.
3) A mechanical problem with the engine making it harder to rotate than it's supposed to be.

Yep. I would say low batt or bad connections. Check your charging system. You know make sure the charger is on that the shore power is working. Go below and rank on all your big cables make sure are all tight.

Just my thoughts. That's what I would do.

Check the simple things first.

SD

I think he had a big thread on how his "wiring project was done" not too long ago...

rwidman said:

What makes you so certain it's not the battery cables? And how about the connections? How about the negative cable attached to the engine?

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*sigh* You guys REALLY need to pay closer attention. I spent all last winter fixing up my DC system.

http://www.trawlerforum.com/forums/s4/winter-project-i-charging-system-upgrade-5641.html

The night before was in the 20's.

Any time you do anything new you always have to go over it a couple of times Just to be sure it is as intended. A connection could have vibrated loose. A little corrosion. anything. Most electrical problems are usually due to the ground wire.

SD

The FL120 does not have glow plugs or any sort of intake air pre-heat system on it. Our Onan generator, on the other hand, has both. Its start battery is a 4D. Even on the coldest of days that we've been out (rarely below 32 degrees, however), the generator always fires up nice and smooth after a minute of pre-heat (one minute is the limit on pre-heat time).

There have been a couple of instances in years past when we've been out on cold Christmas or New Year's cruises and have started the generator in the morning to power a heater in the engine room to get its temperature up before starting the Lehmans.

Marin said:

There have been a couple of instances in years past when we've been out on cold Christmas or New Year's cruises and have started the generator in the morning to power a heater in the engine room to get its temperature up before starting the Lehmans.

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If that makes you feel good there's no harm in exercising your generator but its unlikely to have much impact on those old Lehman blocks. Next time you do this take your infrared thermometer (you do have one I hope - Marilyn likes to use mine for bread making - but I digress). Shoot the ouboard side of each engine before and after you warm up the engine room air.

Back to the OP, one big impact on startability is oil viscosity. If you happen to be running 40W that could explain hard starts around 20F. If it isn't oil then I'd take that same IR thermometer and shoot every connection between the batteries and the starter after a cranking episode. I know you just rewired it but s*** happens. Like Ron said, its your money, go ahead and throw parts at it if you want but that's an expensive way to solve a problem.

GonzoF1 said:

*sigh* You guys REALLY need to pay closer attention. I spent all last winter fixing up my DC system.

http://www.trawlerforum.com/forums/s4/winter-project-i-charging-system-upgrade-5641.html

The night before was in the 20's.

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And how am I supposed to know this?

But even if you spent all last winter fixing up your DC system, how do we know it was done correctly and how do we know nothing has happened to it since last winter?

I assume you started this thread because you wanted help with your problem. I'm just trying to help. If you don't want my help, just say so.

...............................

bobofthenorth said:

If that makes you feel good there's no harm in exercising your generator but its unlikely to have much impact on those old Lehman blocks. .

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We're not trying to heat up the blocks although after an hour of heating the engine room they are no longer cold to the touch. We want to warm up the air and the fuel in the lines that are going to go into the engines on startup.

rwidman said:

But even if you spent all last winter fixing up your DC system, how do we know it was done correctly and how do we know nothing has happened to it since last winter?

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Why, because I used TINNED wire, of course! :lol:
(Sorry, I figured you were in on at least one of the threads I had going about it.)

GonzoF1 said:

Why, because I used TINNED wire, of course! :lol:
(Sorry, I figured you were in on at least one of the threads I had going about it.)

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You screwed up big time unless you had a pro do it ....or had one lecturing over your shoulder anbout ABYC recommendations with the grand finale of having a surveyor report to the insurance company how your boat is better and safer than everyone elses....

psneeld said:

You screwed up big time unless you had a pro do it ....or had one lecturing over your shoulder anbout ABYC recommendations with the grand finale of having a surveyor report to the insurance company how your boat is better and safer than everyone elses....

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OH DAMMIT!!! I guess I will just rip it all out.