Westerbeke 7.6BTD

[Strecker25]

Hey guys, our 7.6btd only has 130 hours on it since 2002 and 40 of them were put on by us in the last two years.

it starts right up and runs ok but at the end of last year and now into this season it’s hunting just a tiny bit without load. If I put a load on it the voltage smooths out

it smokes a little bit at startup but that cleans up quickly. It does also leave a very small exhaust sheen on the water at times

I’ve replaced the fuel filters, both the racor and the pill, but that’s about all I’ve done so far. I do have the service manual and it looks like there are some DIY overhead adjustments that can be checked/made and I also see the process for synchronizing the injectors.

I’m not sure how much of this I’ll DIY as I do have a diesel mechanic buddy who can help but curious….has anyone had to troubleshoot anything similar? My guess is underuse and lots of sitting for 20 years is working itself out and possibly the governor needs some adjustment

 

[dtfeld]

Fuel and filters are my first thought too. Get your fluke and check the electrical frequency no load and full load.

This gen per the manual has 3 filters…the rancor, the “pill” right in front of the fuel lift pump there is a cartridge filter. The pill might not be be there anymore, but the cartridge is for sure.

Maybe check the govenor is free, and lubed.

Beyond that, retorque the head, reset the rack, and have the injectors cleaned serviced.

 

[Strecker25]

Fuel and filters are my first thought too. Get your fluke and check the electrical frequency no load and full load.

This gen per the manual has 3 filters…the rancor, the “pill” right in front of the fuel lift pump there is a cartridge filter. The pill might not be be there anymore, but the cartridge is for sure.

Maybe check the govenor is free, and lubed.

Beyond that, retorque the head, reset the rack, and have the injectors cleaned serviced.

I forgot about that third filter. I ordered it so its sitting in my parts box just never got to it. I'll definitely try that next

 

[LMBoat]

I had the same issue on my 10BTD (very similar to yours). It took a while to resolve, but the fix was free. When it starts to hunt, watch the fuel valve solenoid. If it is retracting and extending, try holding it open and see if the hunting stops. If it does, the problem is electrical. Check all your connections. For me, just unplugging and replugging the main connector in the electrical box on the generator fixed my problem. Or it could be the fuel solenoid itself is going bad.

If the fuel valve solenoid remains still during the hunting, your problem is most likely fuel related.

Good luck, let us know how it goes.

Larry

 

[fwebster]

Hunting or surging is typical of low use diesel Westerbekes. They are designed to run under full load so the fuel injected is a bit rich for low load running. That can cause the injector tips to get fouled which amplifies the richness of the fuel charge since the injectors will spray droplets of fuel rather than atomize the fuel charge. The firsrt thing to do……and you have already done it is to change the fuel filters, next, take the boat out and start the generator then fully load it by turning on the refrigerator, the AC's , etc. for most of a day. Last, remove the injectors and send them to a diesel service shop and have them pop tested on a test stand. That is a test where the technician pumps high pressure solvent thru the injector to visually check its spray pattern. The solvent usually cleans the injector tips but the test will also identify a bad spray pattern and if the bad injector needs to be disassembled and rebuilt it shows the shop what needs to be done.

Just pop testing the injectors is acout $25 each………(Gulf Coast pricing) and you can ask the diesel shop what a rebuild would cost, but these are simple injectors and a clean/rebuild wold be a lot cheaper than a new injector. If the Westerbeke is runninjg ok under a full load, then there isn't a lot wrong with the injectors.


Frank

 

[Carver370]

I forgot about that third filter. I ordered it so its sitting in my parts box just never got to it. I'll definitely try that next

Learned something new today. Do you have a part number for that small inlet fuel filter?

I just finished replacing the Racor and pill bottle filter yesterday.

My gen doesn’t hunt at all, and since I’ve owned the boat I use it every time I’m out. I’m looking at having the valves adjusted this season, I sometimes have a slight sheen on the water while the generator is running.

 

[Strecker25]

Thanks all, I’ll check that stuff this weekend and replace that last fuel filter

the local shop can do all the injector testing a servicing so it might be worth the cost of admission no matter what, but I’ll see if the easy fixes resolve the problem first

 

[ttmott]

To add - low use also can affect the Governor operation. The moving parts of the governor are very sensitive to corrosion and must move smoothly. If the generator isn't run then these parts are not bathed in oil. Many times RPM hunting is caused by the governor not functioning correctly -

 

[Strecker25]

To add - low use also can affect the Governor operation. The moving parts of the governor are very sensitive to corrosion and must move smoothly. If the generator isn't run then these parts are not bathed in oil. Many times RPM hunting is caused by the governor not functioning correctly -

View attachment 124857View attachment 124858

thanks. I’m sure all of this is from many years or no use. It’s the only complaint I had about the boat, the seller thought “only 90 hours on the Gen” was a good thing and I knew it would end up being a problem

 

[dtfeld]

One thing to try before tearing into it too far, dose your fuel with Power Services Diesel Kleen +Cetane Boost, then load it up and run it hard for a couple hours.

Maybe a good hard hot run will clean it up.

 

[Strecker25]

One thing to try before tearing into it too far, dose your fuel with Power Services Diesel Kleen +Cetane Boost, then load it up and run it hard for a couple hours.

Maybe a good hard hot run will clean it up.

yeah our mechanic said a similar thing, load the racor with some injector cleaner and load it up. Although we run it while we’re out the AC cycles infrequently and the water is generally always hot before we leave the dock so the Gen usually has a light load.

next time im at the boat I’ll run it first thing so the HWH and AC’s have to run for a while.

 

[dtfeld]

yeah our mechanic said a similar thing, load the racor with some injector cleaner and load it up. Although we run it while we’re out the AC cycles infrequently and the water is generally always hot before we leave the dock so the Gen usually has a light load.

next time im at the boat I’ll run it first thing so the HWH and AC’s have to run for a while.

Use the stove to load it up. Boil a couple pots of water at the same time.

 

[kevin27]

Can't tell you how many times I hear this . My gen only has xxx hours. I laugh and tell them get ready for trouble. I bought one boat that had 26hours on the gen. Took me another 150 hour to get it happy.

Low hours is very bad. The current gen I have has 3200 hours and I run the crap out of it. Runs perfectly.