Simon_and_Tanja
Well-Known Member
Hi All,
I have a Volvo-Penta MD5a auxilliary of indeterminate (but obviously significant) age which I love for it's classic simple engineering but worry about because it's more fragile than I would like - parts seem very hard to obtain. Came with the boat which I acquired just less than a year ago but was supposedly reconditioned about 60 hours (and 4 years!) ago. Post-purchase, I had it serviced (at huge cost) and found afterwards the injector pump was weeping (externally) and subsequently had to bleed the high pressure lines everytime we needed to start the engine. This, I have fixed with a new o' ring and washer at the delivery valve holder and now all well-and-good. Note: the problem below predates the injector pump weep.
However ...
Occaisionally she (are engines women?) settles into a very fast idle. Maybe 150% of normal. Once switched into gear (and under load) the revs return to normal. Sometimes she idles as expected, sometimes she races, there doesn't seem to be any pattern but whichever speed she has chosen will normally hold steady for 5 or 10 minutes and then maybe (but only occaisionally) wander off to another setting.
The cold-start lever observered working (and returning) correctly but I haven't been using this for the past 1 or 2 months.
I suppose this might be as simple as the throttle control cable sticking somewhere but it's quite hard to observe. Is the cable push-pull or is there a sprung return? Are the cables serviceable or do I have to shell out for a replacement?
Any other likely candidates for the issues with idle speed?
I worry about the governor? But the engine speed at throttle positions other than idle seems consistent and steady (whether in gear or not).
One last question ...
How lumpy? Yes I know it's a single cylinder diesel but she seems to be giving the engine mounts a good workout (maybe I need to check them too). I would have thought that lovely big flywheel would dampen out harsh vibrations but have no experience to guide me. How do other forumrites with MD5 experience feel vibrations? Should it be rattling the wine glases in the galley?
Many thanks,
I have a Volvo-Penta MD5a auxilliary of indeterminate (but obviously significant) age which I love for it's classic simple engineering but worry about because it's more fragile than I would like - parts seem very hard to obtain. Came with the boat which I acquired just less than a year ago but was supposedly reconditioned about 60 hours (and 4 years!) ago. Post-purchase, I had it serviced (at huge cost) and found afterwards the injector pump was weeping (externally) and subsequently had to bleed the high pressure lines everytime we needed to start the engine. This, I have fixed with a new o' ring and washer at the delivery valve holder and now all well-and-good. Note: the problem below predates the injector pump weep.
However ...
Occaisionally she (are engines women?) settles into a very fast idle. Maybe 150% of normal. Once switched into gear (and under load) the revs return to normal. Sometimes she idles as expected, sometimes she races, there doesn't seem to be any pattern but whichever speed she has chosen will normally hold steady for 5 or 10 minutes and then maybe (but only occaisionally) wander off to another setting.
The cold-start lever observered working (and returning) correctly but I haven't been using this for the past 1 or 2 months.
I suppose this might be as simple as the throttle control cable sticking somewhere but it's quite hard to observe. Is the cable push-pull or is there a sprung return? Are the cables serviceable or do I have to shell out for a replacement?
Any other likely candidates for the issues with idle speed?
I worry about the governor? But the engine speed at throttle positions other than idle seems consistent and steady (whether in gear or not).
One last question ...
How lumpy? Yes I know it's a single cylinder diesel but she seems to be giving the engine mounts a good workout (maybe I need to check them too). I would have thought that lovely big flywheel would dampen out harsh vibrations but have no experience to guide me. How do other forumrites with MD5 experience feel vibrations? Should it be rattling the wine glases in the galley?
Many thanks,