Westerbeke 6.5 generator pulsating while running

[Cam.H]

Hello Boaters,

This is my first year of enjoying our 2002 SeaRay Sundancer 360 which has a Westerbeke 6.5KW generator on board. I have not needed to use the generator for operational needs but have, 2 or 3 times now, turned on the Genny and let it run for 15 minutes or so to ensure it is operational and ready to go. The last 2 times I have noticed that once it is warmed up, it seems to cycle or pulsate while running. Hard to describe but it seems to surge up and down a few hundred RPM's when warm. I have not put a large load on it but did use the AC and it seemed to stop the pulsating a bit. Is this something common? I have read up a bit about this and advice is to check the raw water intake screen (I did, not really dirty) or possibly a fuel filter. Just checking in with this knowledgeable group to see if this is how these genny's run when not under a heavy load.

Last time I tested the genny, I didn't use the air conditioner because, as fate would have it, when the compressor goes to engage, the breaker trips. That is a whole other story and looks like I am looking for a new AC unit.


Thanks!

Cam

 

[dtfeld]

Some others with a similar generator might chime in, but I believe the gas Westerbekes have a governor system that requires a specific quantity of oil, or you'll get hunting for the right RPM.

 

[dwna1a]

I’m not sure on this for your set. But it only takes a second. Look up your set on Westerbeke and find the Governor. If it is oil cooled check it’s oil level. It takes 30W and around 2.5oz. It’s very sensitive when it comes to that oil level. Also a good tuneup, including the carb and it’s timing. I love my Westerbeke but I swear it’s a better anchor.

One other thing, the gov spring can get weak and can cause the issue in question.

 

[Cam.H]

I’m not sure on this for your set. But it only takes a second. Look up your set on Westerbeke and find the Governor. If it is oil cooled check it’s oil level. It takes 30W and around 2.5oz. It’s very sensitive when it comes to that oil level. Also a good tuneup, including the carb and it’s timing. I love my Westerbeke but I swear it’s a better anchor.

One other thing, the gov spring can get weak and can cause the issue in question.

Much thanks for this and to DTFeld for the comment. I greatly appreciate it and will take a look when at the boat next. The previous owner did tell me that the genny can be a bit temperamental when it comes to coolant and oil level... I just didn't ask what happens if they are off. Thank you again

 

[bfernald0]

Hello Boaters,

This is my first year of enjoying our 2002 SeaRay Sundancer 360 which has a Westerbeke 6.5KW generator on board. I have not needed to use the generator for operational needs but have, 2 or 3 times now, turned on the Genny and let it run for 15 minutes or so to ensure it is operational and ready to go. The last 2 times I have noticed that once it is warmed up, it seems to cycle or pulsate while running. Hard to describe but it seems to surge up and down a few hundred RPM's when warm. I have not put a large load on it but did use the AC and it seemed to stop the pulsating a bit. Is this something common? I have read up a bit about this and advice is to check the raw water intake screen (I did, not really dirty) or possibly a fuel filter. Just checking in with this knowledgeable group to see if this is how these genny's run when not under a heavy load.

Last time I tested the genny, I didn't use the air conditioner because, as fate would have it, when the compressor goes to engage, the breaker trips. That is a whole other story and looks like I am looking for a new AC unit.


Thanks!

Cam

I have a 2001 340 Sundancer with the 4.5 BCBG Westerbeke. I had the identical problem. It would start surging after it warmed up. While I looked at the governor, it was not the cause of the surging. Still worth checking the oil in governor, but don't start adjusting it until you've run everything else to ground.

In my case it was the carburetor. On the 4.5 anyway, the carburetors were built by Weber out of Italy. They are very sensitive to any crap in the fuel. The inline filter on these are the bare minimum. I ended up adding a water separating filter, and changed the inline filter to something more robust. I rebuilt the carburetor the first time around with a Sierra kit. Didn't take. Spent the money on the Westerbeke kit (in your case though it's 155 bucks at discount marine). Between the rebuild and the additional filters, I've had three seasons now of flawless operation. Runs like a champ.

I found that when I held the "preheat" button down (which on the gas engines is the choke), it would relieve the surging. Might try that to see if the result is the same before you dig into the carburetor.

As as an aside, the Westerbeke site has a lot of materials on these old generators. I checked the 6.5. It has the parts manual, service manual and the regular manual all available for download. No carburetor kit on there, but as stated discountmarine.com has them.

 

[Cam.H]

Much thanks for this information! You are correct regarding the "preheat" button. When I hold it down, the genny runs smoothly. From what you have outlined, this is therefore NOT a carburetor issue if I read your reply correctly? I will check for oil in the governor and read up on the manual again. I admit I am a bit lost with a water separating filter and where that goes but can take a look. Again, greatly appreciate this as it appears I have the same issue that you had.

Keep well

Cam

 

[bfernald0]

Much thanks for this information! You are correct regarding the "preheat" button. When I hold it down, the genny runs smoothly. From what you have outlined, this is therefore NOT a carburetor issue if I read your reply correctly? I will check for oil in the governor and read up on the manual again. I admit I am a bit lost with a water separating filter and where that goes but can take a look. Again, greatly appreciate this as it appears I have the same issue that you had.

Keep well

Cam

Quite the opposite. If you choke it and it runs fine, it likely IS the carburetor.

Also, I pulled up the parts manual on the 2002 360 Sundancer. You're right, it has an inline water separating filter. No such item on my 340. I added one.

I also note that the fuel pump appears to have a screen in it (see the excerpt from the parts manual below).

When I dealt with this, my assumption was that it wasn't getting enough fuel, which caused the surging. When you choke it, it richens up the mixture and stops the surging. (I'm no carburetor expert).

I would do the following:

Change the fuel filter.

If that doesn't solve it, I'd remove the carburetor, take off the bowl (mine had a bunch of crap in it) and use carburetor cleaner to blast everything.

If that doesn't solve it, I'd probably swap out the fuel pump. You should be able to get a non-OEM replacement--I did on mine.

If that doesn't solve it, I'd rebuild the carb with the OEM kit.

These Westerbekes are an amalgamation of components from other manufacturers. I believe the block on these is Daihatsu (at least mine was and was used in those tri wheel minicabs you see in the movies in Asia), the carburetor is weber, etc. If you do your google searching, you'll find non-OEM replacements for a lot of the components.

As stated, however, I did not have a lot of luck with the Sierra rebuilt kit. I'd buy Westerbeke one or try and find the equivalent Weber one.

Good luck.

 

[bfernald0]

Parts manual for a 2002 360 Sundancer shows a water separating filter for the generator. Nice add.

Follow the fuel line back from the generator. Should be there somewhere. I'd start by replacing that. May solve your problem.

 

[Cam.H]

I really can't thank you enough for all of this. The details here will help me as I have limited mechanical experience and knowledge. I was speaking with the previous owner just the other day and he is mechanically inclined. He advised he had changed out the fuel filter and water separating filter last fall when the boat was pulled out. He said he did this as the genny had been surging. He also left me a spare filter which is great. I like your idea of checking the carburetor bowl and then likely change out the fuel pump. Sorry I misunderstood you and that it likely is a carburetor issue as it runs better when choked.

I will let you know! Again, MUCH THANKS

 

[Cam.H]

I should also have added that the previous owner did tell me that these genny's are VERY temperamental. He said that they don't like too much or too little oil or coolant as this can impact their performance. It does run much more smoothly when it has a load on it such as water heater and the cabin AC

 

[bfernald0]

I should also have added that the previous owner did tell me that these genny's are VERY temperamental. He said that they don't like too much or too little oil or coolant as this can impact their performance. It does run much more smoothly when it has a load on it such as water heater and the cabin AC

Good luck. Since I rebuilt the carburetor with the OEM kit, the generator has been absolutely rock solid (I'm knocking on wood as I'm typing this).

Here's a video of mine surging. Please ignore the inappropriate 'tool' sitting on top of the air cleaner. I had it sent to my mechanic's shop as punishment for the repower taking so friggin' long.

When I bought the boat in 2019, it had 180 hours on the motors and 25 on the generator. Unfortunately, in that short period of time the seawater pump had developed a small leak, which over 20 years made an absolute mess of the front of the motor. Once the engines were out, I took the generator home and cleaned it up, only to deal with the surging issue once it was reinstalled and actually running.

https://www.amazon.com/photos/shared/Je__FwMuQjSLdQj75MuwZw.0PoLQLS5VrgrLTmbenwzNP

 

[Cam.H]

I won't comment on the "tool" matter ha ha ha

That is my genny to a T. Sounds just like that

 

[bfernald0]

I won't comment on the "tool" matter ha ha ha

That is my genny to a T. Sounds just like that

Rebuilding the carb is not as hard as it sounds. All you're really doing is replacing a few parts that come in the kit. Unhook the throttle linkage, unscrew the carburetor bolts, remove the entire carburetor, and stuff a wad of paper towels or rags into the manifold opening to prevent you from dropping anything into the intake manifold (one errant screw goes down the manifold and you'll be taking the entire manifold off to find it).

Take the carb home to a work bench, take off the bowl and use carburetor cleaner to blow out all the jets, clean out the bowl, etc.

The kit is comprised basically of some new seals, a new needle valve, new internal filter, new main jet, and a few orings. Much to my wife's chagrin, I took the carb apart on the kitchen counter, took the components outside to blow out with the carburetor cleaner, and then replaced all the parts in the kit, put it back together, reinstalled it, and it's been good to go ever since. Alternatively, find a local engine shop that does carburetors and deliver the carb and kit to them to rebuild.

 

[dwna1a]

Broke mine down and soaked it in a old crockpot full of cleaner. Had it back on the set the next night. Adjustments were the worst for me but a buddy had it done in about twenty minutes