mickywillis
Well-Known Member
Many of you nice peeps on the forum have offered answers/solutions to my ongoing problems with my engine in my Westerly Pageant, Zara ( see http://www.ybw.com/forums/showthread.php?t=288148 for ongoing saga!!)
She was launched again in late March and during the winter, I had the injector rebuilt by Watsons Diesels and had the prop re-pitched by T Norris, in the hope that these may cure my problem.
When taken up Langstone Harbour for a test run 2 weeks ago, Zara felt worse than ever. Barely able to make 3 Kts, we struggled to get past the entrance of the harbour against the tide. In fact, we turned round and came back in to the mooring for fear of breaking down and having to sail onto mooring or get a tow back.
So this weekend I decided to change all the filters again, change the bleed screws, O rings and anything that would possibly let any air into the system. If this didn't cure the problem, I resolved myself to remove the cylinder head, check bore wear, reseat the valves and look for any problems due to loss of compression.
To gain better access to the engine filter ( the one bolted onto the rear of a Yanmar 1GM10) I decided to remove the whole assembly so I could renew the filter, O ring and the 2 bleed screws on the top of the housing. When I removed the aluminium bowl, I noticed tha the paper element filter was crushed and slightly twisted. I had noticed this when I changed the filter in July, but put this down to the fact that I was using non genuine Yanmar filters and that they may be a little too long for the housing.
When I started to remove the bleed screws, I inverted the housing and looked onto the spigot where the filter pushes onto. Something didn't look right?
Inspection revealed the metal disc of an old filter had remained on the spigot. This was why the old filters had crushed and distorted slghtly, but had been able to just about fit on the spigot. The act of tightening the filter housing securing ring pushed the new filter against the remaining disc, enough to form a seal and to not cause problems at times of minimal fuel demand. But once the lift pump tried to allow more fuel to the injection pump, air was being drawn into the sytem at the intersection where the 2 metal discs contacted. A previous test with a seperate fuel tank also didn't highlight the problem as the filter is installed between the lift pump and the high pressure pump.
I removed the metal disc, refitted the new filter, bled the system and serviced the rest of the engine.
The little Yanmar now runs like it did when we first had her! It sounds smooth, powerful and strong, in fact I feel that all the other works carried out have given the boat a much greater turn of speed and pushes the hull up to design speed quite happily. The repitching of the prop seems to allow the motor to rev more freely, but I haven't had a chance to put my rev counter on the crank pulley to see what max revs are under full load. At no load on the jetty, the motor will now rev to 3800 RPM (previusly 3200RPM) so it will be really interesting to see what she runs at at full bore, under load in gear.
Hopefully the pictures below will give an idea of what I found (this is a spare filter housing I have, not the one on the boat, but the disc and filter are the ones removed)
Interestingly enough, when the housing was fitted on the engine, the metal disc could not be seen due to the engine location within the boat and the obscured view afforded from the engine hatch and the cockpit access. Not only did I not spot it, but neither did the marine engineer who worked on the boat when we broke down in Ryde last year (not his fault as I say, it couldn't have been seen unless the housing was removed from the engine)
I service the motor each April when she goes into the water and I really do not remember seeing or removing the filter element without the metal disc on the top.
So a big thanks for all your suggestions and hopefully my problems and resolution may be able to help someone suffering a similar problem. I had checked all the usual (and suggested) points of possible air entry into the fuel lines, but no-one came up with this as a possible cause to the problem - perhaps this is a first?
She was launched again in late March and during the winter, I had the injector rebuilt by Watsons Diesels and had the prop re-pitched by T Norris, in the hope that these may cure my problem.
When taken up Langstone Harbour for a test run 2 weeks ago, Zara felt worse than ever. Barely able to make 3 Kts, we struggled to get past the entrance of the harbour against the tide. In fact, we turned round and came back in to the mooring for fear of breaking down and having to sail onto mooring or get a tow back.
So this weekend I decided to change all the filters again, change the bleed screws, O rings and anything that would possibly let any air into the system. If this didn't cure the problem, I resolved myself to remove the cylinder head, check bore wear, reseat the valves and look for any problems due to loss of compression.
To gain better access to the engine filter ( the one bolted onto the rear of a Yanmar 1GM10) I decided to remove the whole assembly so I could renew the filter, O ring and the 2 bleed screws on the top of the housing. When I removed the aluminium bowl, I noticed tha the paper element filter was crushed and slightly twisted. I had noticed this when I changed the filter in July, but put this down to the fact that I was using non genuine Yanmar filters and that they may be a little too long for the housing.
When I started to remove the bleed screws, I inverted the housing and looked onto the spigot where the filter pushes onto. Something didn't look right?
Inspection revealed the metal disc of an old filter had remained on the spigot. This was why the old filters had crushed and distorted slghtly, but had been able to just about fit on the spigot. The act of tightening the filter housing securing ring pushed the new filter against the remaining disc, enough to form a seal and to not cause problems at times of minimal fuel demand. But once the lift pump tried to allow more fuel to the injection pump, air was being drawn into the sytem at the intersection where the 2 metal discs contacted. A previous test with a seperate fuel tank also didn't highlight the problem as the filter is installed between the lift pump and the high pressure pump.
I removed the metal disc, refitted the new filter, bled the system and serviced the rest of the engine.
The little Yanmar now runs like it did when we first had her! It sounds smooth, powerful and strong, in fact I feel that all the other works carried out have given the boat a much greater turn of speed and pushes the hull up to design speed quite happily. The repitching of the prop seems to allow the motor to rev more freely, but I haven't had a chance to put my rev counter on the crank pulley to see what max revs are under full load. At no load on the jetty, the motor will now rev to 3800 RPM (previusly 3200RPM) so it will be really interesting to see what she runs at at full bore, under load in gear.
Hopefully the pictures below will give an idea of what I found (this is a spare filter housing I have, not the one on the boat, but the disc and filter are the ones removed)
Interestingly enough, when the housing was fitted on the engine, the metal disc could not be seen due to the engine location within the boat and the obscured view afforded from the engine hatch and the cockpit access. Not only did I not spot it, but neither did the marine engineer who worked on the boat when we broke down in Ryde last year (not his fault as I say, it couldn't have been seen unless the housing was removed from the engine)
I service the motor each April when she goes into the water and I really do not remember seeing or removing the filter element without the metal disc on the top.
So a big thanks for all your suggestions and hopefully my problems and resolution may be able to help someone suffering a similar problem. I had checked all the usual (and suggested) points of possible air entry into the fuel lines, but no-one came up with this as a possible cause to the problem - perhaps this is a first?
