Eractic Tachometer and engine power

[Guan]

My 2001 B361 westerbeke tachometer starts up from 0 and jumps to 2500 and back to 0 on minimal acceleration a few times then settle to normal.
Any suggestions to remedy this?
Sorry if old question buy cannot find previous similar posts.
Loose wires? or harbinger of junk engine @ 1700 hrs.
Also first outing this year engine noticed to be weak on full throttle.boat going 4 knots max..old 2019 fuel?
Thanks again guys.
Hope everyone is in great health for the coming sailing season.

 

[odaydokay]

Regarding the 4 knots, was the stuffing box just adjusted and maybe too tightly? Got a nice free spin on your prop? I came out of my yard once with a piece of clear plastic used in the sling wrapped around my prop. My revs were not impressive, reversing for a bit spun it off. Goofy stuff happens. (Unfortunately an erratic tach is not helpful as a troubleshooting tool.)

 

[Don S/V ILLusion]

When was the last time you removed and cleaned all electrical connections?

When was last time hull/prop cleaned?

Was knotmeter precision checked against GPS speed or other reference?

 

[sailcapt340]

There should be a sensor located somewhere on the bell housing of the transmission. Remove the 2 wires and check for corrosion. A little steel wool to clean up each side should be all you need if there is corrosion.

 

[Hello Below]

steel wool

Steel wool on a boat Say it ain’t so, Joe.

 

[Guan]

There should be a sensor located somewhere on the bell housing of the transmission. Remove the 2 wires and check for corrosion. A little steel wool to clean up each side should be all you need if there is corrosion.

When was the last time you removed and cleaned all electrical connections?

When was last time hull/prop cleaned?

Was knotmeter precision checked against GPS speed or other reference?

Regarding the 4 knots, was the stuffing box just adjusted and maybe too tightly? Got a nice free spin on your prop? I came out of my yard once with a piece of clear plastic used in the sling wrapped around my prop. My revs were not impressive, reversing for a bit spun it off. Goofy stuff happens. (Unfortunately an erratic tach is not helpful as a troubleshooting tool.)

Thanks for all kind instant suggestions. Will do all when old hip pains and weather improves. Regards and most obliged again guys.

 

[Guan]

There should be a sensor located somewhere on the bell housing of the transmission. Remove the 2 wires and check for corrosion. A little steel wool to clean up each side should be all you need if there is corrosion.

Ahoy Capt340, I cannot find the bell housing.
are the tacho wires connected to the alternator or transmission?
sorry for such a naive query but I'm really a boat wiring goon!
thanks.
Guan

 

[Guan]

Gps sog was 7.5mph

 

[sailcapt340]

What is your Westerbeke model number? If we had that others could identify it and give you some insight as to the sensors possible location. Following wires can be an impossible task.

 

[Guan]

What is your Westerbeke model number? If we had that others could identify it and give you some insight as to the sensors possible location. Following wires can be an impossible task.

will try to read that facing a very narrow s ace and seems very salt corroded.
All wire fittings behind the alternator was tight.

 

[Guan]

Westerbeke 30B3 2001 boat

 

[higgs]

You may have two problems. You speak of lack of power with full throttle and also the tach issue. On the lack of power, first thing I would do is replace all fuel filters and bleed the system. Far and away most diesel problems are fuel related. As for the tach - I agree with those who say clean contacts to the sensor which will be located somewhere around the bell housing. It is also possible the senor is is malfunctioning. You will need a manual for your engine to know what the electrical meter reading should be for your sensor.

 

[Guan]

thanks again

 

[sailcapt340]

Now that you have the Engine Model number, don’t know if you have a manual for this engine or not. Here is a link to the manual for that model. Transmission info starts on page 47. Seems you may have to trace the wiring from the Tachometer back.
Sometimes 2 people are needed as you can pull on a wire in a harness and another can see it move, ever so slightly at times, in the harness downstream from the Tachometer. Then move on from there.

WESTERBEKE 30B THREE OPERATOR'S MANUAL Pdf Download

View and Download Westerbeke 30B Three operator's manual online. Marine Diesel Engines. 30B Three engine pdf manual download. Also for: 20b two.

www.manualslib.com

It’s time consuming and hard work but can be done.

 

[capta]

There should be a sensor located somewhere on the bell housing of the transmission. Remove the 2 wires and check for corrosion. A little steel wool to clean up each side should be all you need if there is corrosion.

That should be the neutral start switch and should have nothing to do with the engine if it is running. I always deactivate mine because when I need the engine to start I want it to. However, this is not a good idea if one is not good at situational awareness (like not checking that the boat is in neutral before starting) or if one has a substance abuse or drinking problem (not joking).