1800 RPM Kohler vs 3600 RPM Westerbeke

[vineyardgray]

The Kohler generator I have is a 7.4 KW 1800 RPM unit that generally runs but is ailing and most parts are NLA.

I have been eyeing used westerbeke units and most I can find are only 5kw, which is probably fine but also are 3600rpm.

How much louder will a 3600 be vs an 1800? Will the "exhaust tone" be that much more annoying vs the low rumble of an 1800 RPM unit?

[ColRon]

Matt,

My previous boat, Moody Blue, had an Onan 4KW single cylinder genset that ran at 3600rpm. There isn't anyway on God's green earth I would ever want one of those screaming meanies again. While the exhaust noise was louder, it was the sound of the engine, not the exhaust that really made the difference. It was SIGNIFICANTLY louder than my 1800rpm 4 cylinder Kohler. You couldn't sit in the cockpit and have a normal conversation it was so loud.

[bud37]

I agree with Ron.....I have had both, and old flathead four Kohler 1800 rpm, dead quiet exhaust. Loved it.

Now we have this 3600 rpm revmaster 7200 ( thats what I call it )....its in an insulated box, fairly quiet exhaust but it has a sound to it that I don't like, it starts up instant on kill....this makes it eat water pumps, is hard on parts as there is no warm up. Basically a 2 cylinder lawn tractor engine with only a 2 pole gen head.

My opinion is , if it was my choice, I would only buy the 1800 rpm model, I just believe them to be made a lot better. Get one you can maintain easily when in position in the boat, this means changing the water pump impellor/ oil changes.

What cost differences are you seeing here ??

[Cooler]

On behalf of the boating neighbors at the same anchorage,...please go with the 1800 rpm models. It is really annoying when we are sitting in the bridge, enjoying that black starry night, sipping a beverage, warm sea breeze blowing thru our no hair, Boz Scaggs crooning "Love - look what you've done to me", and then........BRAACK, pa pa pa pa pa pa pa pa etc. Just wrecks the romance. Besides, Kohler is a great company, located just 60 miles from me, and will back up their products with great support. Had a pressure washer motor that cracked a muffler piece after 2 years. They replaced the entire engine and restarted the 3 yr warranty. That was 10 years ago, and it is still running great! er

[tomschauer]

I do believe all of the current gas generators, Kohler included are 3600 rpm.

[Keith S]

Kohler has been out of the marine gas generator business for 2 years now. Westerbeke is the only game in town. Except for the the smallest unit, the 3.5kw, all Westerbeke generators have been 1800 rpm for quite a few years. You probably would be looking at the 7.5MCGA. It is smooth running and quiet, but not cheap. Due to emissions regulations, they are muli-port EFI with catalytic converters. The advantages are a very fuel efficient. low CO unit. The disadvantage is the price reflects those expensive things.

[ColRon]

Matt, while parts are not easy to find they are still out there, some NOS and some aftermarket. The L654 engine used on the Kohler 7.5R was a popular engine for genset use in both Marine, RV and standby sets. Kohler even had one that ran on LP Gas.

[vineyardgray]

I guess the consensus is I should try to hang onto the old Kohler until she really gives up the ghost. This year I didn't use the generator at all and when I did the heat exchanger got really hot - more than I thought was normal - so I'm assuming something is amiss there. The mechanic said it wouldn't start to winterize so I started looking at parts - which are scarce - and then replacement units.

I kinda hate being being tied to technology that is no longer supported and with scarce or NLA parts.

[km1125]

Source of the post
...This year I didn't use the generator at all....

THAT is what usually kills them.

Source of the postThe mechanic said it wouldn't start to winterize so I started looking at parts - which are scarce - and then replacement units.

So did it get winterized or not? That could be bad if you don't get any trapped water out of there. If I couldn't get it to start, I'd pull off a few hoses and pump some -100 AF in there so you don't ruin the block, because that WOULD spell the end for the unit!