cold weather yanmar 4jh4 hte will not start

[jimbeam]

2008 r25 in real cold weather will not even turnover. I checked battery connections Etc. and all seem tight.
Batteries appear charged but are 6.5 years old. Was told that even appear charged may not have enough cranking amps to
start. I even tried parallel but no go. Tapped on the starter to see if cranking gear works but still no go.
I feel that maybe the batteries are just not giving all the cranking amps to start. New batteries might be in order.
Everything else works, like lights Etc. Weather warms up to over 50 and engine starts but noticed slow crank.
Any suggestions would be appreciated.
Jimbeam :?

 

[bob daily]

Mr. Jim, your biggest problem is the battery, diesel engines don't like cold weather and cranking a cold engine requires more amps. After replacement of your starter battery I would also check the glow plugs, at the age of your boat its time to ensure they are working properly. Next if operating in cold weather I would consider a block heater, they sure make life easier when wanting that engine to start.
You can get a oil dip stick heater or a coolant one that you splice into the lower radiator hose both work great and price is responsible.
Good luck Bob

 

[Favunclerich]

The Yanmar 4JH4-HTE is not equipped with glow plugs. It is equipped with an induction heater. Prior to starting, rotate the key counter-clockwise and hold for ten seconds or so. This will warm the air going into the cylinders and will improve starting. However, if the batteries are too weak to engage the starter and rotate the crankshaft, you'll need a new engine battery. 6.5 years is pretty good for battery life, so this should just be considered normal maintenance, and it's probably a good time to replace them all.

 

[BB marine]

Simple and easy test with a VOA meter. Battery charger off. Check the voltage at the engine battery. Check the voltage at the main battery lead (terminal) going to the starter. Both readings should be the same, 12.5 to 12.7 volts. If yes continue. if no. Weak batteries or bad connection. Leave the VOA attached to the starter main battery terminal. Hit the start button the voltage should drop no more than 2.5 Volts. If more than that the battery is compromised. If there is no voltage drop there may be an issue with the solenoid or starter. My bet is on the batteries being compromised.

Owning a inexpensive load tester is also a quick easy way to confirm battery condition. Old or new the first check of any 12 volt system malfunction is the source of power. The battery voltage and available capacity.

 

[knotflying]

Going along with what Favunclerich said, I would say being in VA you are experiencing very cold weather. As good as your batteries are a diesel with very cold weather will take lots of power to turn over. I would heat up the engine compartment for a while and get the oil to a better viscosity. Many diesels in cold environments have engine heaters. Same principle here.

 

[Favunclerich]

One other thing to check is to see that your boat is wired to start using the engine battery. At least a few of that vintage boats (including mine) were incorrectly wired at the factory to start using the house batteries. That could also explain why the parallel switch did not provide enough additional starting power to crank the engine.

On a separate, but related topic, you can search for the forums on this site discussing the pros and cons of connecting the thruster battery to the house bank. If you were to do that, when you turned on the parallel switch, you would have the capacity of all four batteries available to start the engine.