Fuel injectors (05/2019)

My C270 has the Westerbeke 20B Two engine.

It has been running well, no complaints. To set some context:

However (there has to be a 'however' or I wouldn't be writing this page!), over the last year or so I had been noticing one trouble indicator: When cold, the engine rpms didn't respond very linearly to throttle input.  After it warmed up, throttle response was very linear. The problem was only during the first minute or two after a cold start.

It wasn't really a problem since I let the engine warm a minute or three anyway. By the time I was ready to cast off it was fine. So I was able to ignore it for quite a while but it kept nagging me.

To be very specific: about a year ago if I started the engine cold, it would start right up and idle around 800rpm. If I moved the throttle up just a bit, the engine stayed at 800rpm. I had to move it a bit more and then it would jump to 1000rpm. From that point on, each mm of throttle movement would raise the rpms.

About six months ago, on a cold start, if I raised the throttle up to the 1000rpm position the engine would still stay around 800rpm. I had to raise it more, up to around the 1500rpm position, before the engine would react and move up to 1500rpm.

Last month the problem got so severe there was no more ignoring it. When cold, I could open the throttle to about 90% and the engine would still remain at idle!! After a certain point (say, about 95%) the engine would finally react and race up to 3000rpm.  Even then, as soon as the engine warmed up it was back to normal.

I could not find anything on the web or in books matching these symptoms, so I'm writing this page in case it helps someone who experiences this.

I removed the injectors and started looking for a place to test them. Most places I contacted never got back to me... The few that did, said they didn't know how to deal with marine engines and/or Westerbeke.

Finally I found a place, Diamond Diesel & Turbo Service, in Oakland (California) who said they could check them out. I dropped off the injectors and they recognized them on sight and said they had parts in stock and could do the work right away. They cleaned, tested and rebuilt (replaced the nozzles) the injectors in an afternoon. If you're in NorCal, highly recommended!

Turns out the Westerbeke injectors are Denso 93500-3840, FYI.

Here's a pic of the cleaned injectors:

   


After installing the rebuilt injectors, throttle response on a cold engine is now perfectly linear.



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