FWIW, My diesel mechanic advises 30 microns for primary and 10 microns for secondary. That's what I use on my Universal M4-30. About fifteen years ago I got worried about my fuel being old and pumped it out into jerry cans and replaced with fresh fuel. I added a biocide and I don't have an hour meter but count the number of gallons I burn which is usually 20 to 30 gallons a season. I changed them after seven seasons and they looked fine and the bowl stays clear. I only use diesel from jerry cans and I buy it from busy truckstops to try and keep it as fresh as possible. I also add Seafoam to the fuel and the oil which seems to help starting.
Chuck Scheaffer, Resolute, 1990 C&C 34R > On May 21, 2019 at 9:03 PM Rick Brass via CnC-List <cnc-list@cnc-list.com> > wrote: > > > The OEM fuel filter for my Universal M35B is 10 microns, plus there is a > small “strainer” filter near the inlet to the lift pump. IIRC, the spare > “strainer” that comes in the parts kit is marked as being something like 70 > microns. > > > > The installation manual for the engine suggests using a primary filter > (the Racor) of about 30 microns should you want to add one. Which is > consistent with the advice you gave. > > > > But because I’m anal about abrasive material getting into the high > pressure pump, and because the design flow rate of the Racor filter is > literally 10s ( maybe 100s) of times the 3 to 5 GPH flow rate of the M35B > fuel pump, I’ve elected to use a 5 micron Racor as the primary. > > > > I had to replace the 1st Racor while enroute to Annapolis last fall, with > something over 900 engine hours on the filter, after apparently getting a > tank of crappy fuel the previous day. The engine coughed once while > approaching a marina, then ran for about 15 minutes. When restarted the next > day, it ran a few seconds, stopped, and could not be restarted. The clear > bowl below the filter was totally black with crud. > > > > The failure mode was not that described in Pierre’s post (gradual fuel > starvation after long run period) and seems more consistent with the > overheating lift pump I mentioned in my other comment. > > > > I suppose that an almost plugged filter could cause fuel starvation for a > short while. But once the filter is plugged, the engine will stop and not > restart. > > > > Rick Brass > > Washington, NC > > > > > > > > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Andrew > Burton via CnC-List > Sent: Tuesday, May 21, 2019 5:03 PM. > To: cnc-list@cnc-list.com > Cc: Andrew Burton <a.burton.sai...@gmail.com> > Subject: Re: Stus-List M-35 electrical fuel lift pump > > > > 2 micron might be part of your problem. There’s no need to go that fine > on your filter element. 30 micron is perfectly adequate. Remember you have a > finer filter on your engine. > > The 2 micron can easily clog up and leave the bowl of your Racor clear. > > > > Andy > > Andrew Burton > > 139 Tuckerman Ave > > Middletown, RI > > USA 02842 > > http://www.burtonsailing.com > > +401 965 5260 > > https://sites.google.com/site/andrewburtonyachtservices/ > > > > > > > On May 21, 2019, at 11:46, Pierre Tremblay via CnC-List > <cnc-list@cnc-list.com mailto:cnc-list@cnc-list.com > wrote: > > > > > > Hello all, > > > > > > > > After suffering few fuel starving, I decided to have spare part for > > everything between fuel tank and engine fuel injection pump. Engine is a > > Universal M-35. RPM would slowly drop down then engine dies. I am able to > > start it back by just opening the fuel blead valve on the injection pump. > > It happened after 4 hours motoring in dead calm sea with a full tank, and > > the Racor glass is clear. I had no problem when the engine is cold. I > > suspect the fuel lift pump. > > > > > > > > The electrical fuel lift pump I actually have is a CARTER 7H15A > > 504. Google cannot find it, and the only look alike from Carter is #P60504 > > or #P76438 superseded by #P90091. Can someone tell me what you have for > > lift pump. > > > > > > > > From the spare fuel filter I have, primary (Racor 200FG) is 2 > > micron, and secondary is 10 micron. I know it is wrong and I will go with > > 10 / 10. The 2 micron might also start to be dirty. > > > > > > > > Good wind... > > > > Pierre Tremblay > > > > Avalanche #54988 > > > > C&C38-3 WK, hull #76 > > > > > > > > > > _______________________________________________ > > > > Thanks everyone for supporting this list with your contributions. > > Each and every one is greatly appreciated. If you want to support the list > > - use PayPal to send contribution -- https://www.paypal.me/stumurray > > > > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray > >
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