No alternator

1991 350 CID

Removing alternator because I feel it may be "sick". It is a special 130 amp alternator with twin belts and I want to get it checked

I want to take the boat on a 6 hour trip and I really don't need the alternator as it was mounted to keep 2 8D house batteries charged while underway. I have solar now so keeping the batteries up is not a problem.

Question.....Will removing the alternator and the two belts have any adverse effect on the raw water pumps functionality .

I wouldn't think so but I am not clear on why the two alternator belts run through 3 pulleys....the top pulley, the bottom pulley and the alternator pulley

willow said:

1991 350 CID

I want to take the boat on a 6 hour trip and I really don't need the alternator as it was mounted to keep 2 8D house batteries charged while underway. I have solar now so keeping the batteries up is not a problem.

Question.....Will removing the alternator and the two belts have any adverse effect on the raw water pumps functionality .

I wouldn't think so but I am not clear on why the two alternator belts run through 3 pulleys....the top pulley, the bottom pulley and the alternator pulley

Click to expand...

Re: " house batteries...." What recharges your start battery? ( and runs the engine's electrical system????) If that same alternator charges BOTH the start battery AND the house battery from one output, you have an undesirable condition. Hopefully alternator has TWO outputs, one to charge the start battery and one to charge the house...or you have a charge isolator ???? I'd be nervous on a 6 hour trip to be running the engine's electrical system on a battery that long.

re: top/bottom and alternator pully's... depends on what those pullys do. One may be an "idler" used to adjust belt tension without having to move the alternator on its bracket. Without more info we can't really help much.

Do not run the motor without a good charging system. Are the batteries in good condition and is the wiring in good condition. If you feel it has issues get those issues resolved before you put the boat into service. Not only can it create more expensive repairs how much are the lives on your boat worth?

Thanks Guys.....for your input....

Both START batteries are charged off the alternator that is the normal alternator on the OTHER engine.

The House batteries (2 8D's) are charged by 1900 watts of solar panels when standing still or moving on a sunny day.

If I happen to be moving on a rainy, cloudy day, the 130 amp alternator on the other engine is charging the 2 8Ds and yes, isolators are in place. If I am standing still on a rainy, cloudy day I can ;

(1) fire up the portable Honda 2000 to charge the house batteries
(2) be plugged into shore power and run everything, including dual Dometic roof air conditioners
(3) fire up the Westerbeke 7.0 and run everything, including dual Dometic roof air conditioners

My electrical system is well set up and I have a lot of options available for electrical power..all wiring is in good shape and the entire setup has been checked by two professional electrical engineers

Been running the boat with this setup for many years now except for the addition of all the solar power which was installed 2 years ago...and I love the solar

All batteries in the boat are not over 3 years old ( two start), (four thruster batteries..2 forward, 2 aft...), (two house batteries)

Follow up....
Voyage complete with port engine, large alternator, removed...then this happened...........
About 30 minutes into the trip the port engine showed overheat except when at idle power
Left the engine at idle of one hour thinking that perhaps something was caught under the boat
Still showed overheat above idle.....shut the port engine down and continued with just the starboard engine
Drove the vessel, as the only occupant, 16.5 hours in that configuration with adjustments to balance/trim by cross feeding fuel

Home port....removed the raw water pump and checked bearings and the impeller ....all good
Checked the large alternator I thought might be "sick"....bench checked fully serviceable

Next ???? Pulling the thermostat and checking it ( port engine......the one that started to overheat.)

Now ...if it is not the thermostat...where do I go from there ????????????

On my 2002 350s (single belt) the three pulleys are the crankshaft, the alternator, and the water pump (coolant circulating) that is mounted on center, just above the crank pulley. The raw water pump is mounted on the front of the crankshaft so it will spin without the belt. But the circulating pump will not. Loss of that pump would certainly lead to an overheat. In fact I would expect the cylinder walls to greatly exceed boiling before enough hot fluid worked its way up to the temperature sensor in the intake manifold to show an overheat. I hope this is not your situation as cracking the block or head would be a distinct possibility.

Update...........

The overheated engine's thermostat was removed....which was not easy for an old fella !! Those bolts seemed to be mired in concrete
The thermostat's spring was broken in half and sitting crossways inside the thermostat housing...the thermostat looked really quite bad...no idea why the spring broke.
Thought I should probably do the starboard engine as well. The thermostat looked OK but thought I might as well replace it as well.

Waiting for kits that should be here in "Smallville" in about 2 days.

Will update an engine-run check when all is put back together.