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Discussion Starter #1
My Westerbeke 30B Three propulsion engine, with sail drive, always achieved 3600 max rpm under load, which is the specification. Now I only get approx 3000 rpm under load, but can adjust stop screw to get as high as 3800 rpm at no-load high idle. There had been a deceleration stumble which was finally cleared up by replacing governor springs and fuel control rod. The injectors and injector pump had been tested and serviced by an injector shop and set to specs. The boat bottom was just cleaned and the engine runs fine, with normal temp, oil pressure and noise level, no smoke -- 700 hours on this engine. I'm at a loss to understand why the engine no longer gets to 3600 rpm under load. Any ideas as to a possible fix would be appreciated.
Len
 

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Other than what you have already listed. Compression, Timing, Air intake restrictions, Low fuel pressure and or flow, clogged fuel filter/lines/tank vent. If the basics don't bring you to a conclusion check valve adjustment, valve lobe lift also lobe lift for the injector pump (if it has that type of pump) After that I would check the sail drive for binding etc.
 

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Also check exhaust restrictions or if you have done anything to the exhaust that might affect the performance as well. A poorly tuned exhaust will not allow proper scavenging of the cylinder during the valve overlap between the exhaust and intake stroke. That could rob you of that last little bit of performance you are missing.
 

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Discussion Starter #4
Thank you. So far have checked air intake, tank vent, Racor 500, lift pump output. Exhaust doesn't appear to be restricted. Saildrive seems to turn freely. Need to check on-engine filter, return line, valve adjustment.

Questions: What I read was that fuel pump timing on this engine is adjusted by varying thickness of shim under injector pump body. To my knowledge the shim is the same as before pump was serviced. I'm not quite sure how that shim works to affect timing. The pump has three elements and cam followers. If the timing were too soon or too late what might I notice about the exhaust? Would there be smoke or unburned fuel in expelled raw water? Also, not sure what you mean by "tuned exhaust."

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Other than what you have already listed. Compression, Timing, Air intake restrictions, Low fuel pressure and or flow, clogged fuel filter/lines/tank vent. If the basics don't bring you to a conclusion check valve adjustment, valve lobe lift also lobe lift for the injector pump (if it has that type of pump) After that I would check the sail drive for binding etc.
SECOND QUOTE: Also check exhaust restrictions or if you have done anything to the exhaust that might affect the performance as well. A poorly tuned exhaust will not allow proper scavenging of the cylinder during the valve overlap between the exhaust and intake stroke. That could rob you of that last little bit of performance you are missing.
 

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Courtney the Dancer
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You said the bottom was cleaned, but the most obvious thing that would cause this would be a fouled prop (barnacles), or a prop with a piece of line in it. Start with the basics before you take the injection pump apart.
 

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Discussion Starter #6
Thanks. There's no fouling of prop and I've now checked out just about everything else. This included, for testing, hooking an independent lift pump and supply and return lines directly to injector pump using fresh fuel in a jerry can. In other words, my normal fuel delivery system wasn't used in any way. Same loss of power as before.

As previously noted, the engine runs fine in every way, except that it doesn't produce enough power which it had done. Seems like it's not getting enough fuel.

It appears that this problem arose after my injector pump was rebuilt and that included replacing its pumping elements, and injectors were serviced including replacing their nozzles. Is it possible that the wrong parts were used, meaning pump elements and/or nozzles for another application that don't deliver enough fuel?

My engine is used for propulsion. The same engine is also used in genset applications.
 

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Not familiar with your particular injector pump but if it was not re-installed in the exact same position the timing may be off. It certainly appears that the problem started with the removal and replacement of the injector pump and injectors. As you mentioned, the pump and/or injectors may not have been re-calibrated correctly? Perhaps you can have another shop inspect them. It wouldn't hurt to check the valve clearance but if that was the cause it probably would have been noticed before you had the pump and injectors worked on. As you have isolated your fuel delivery system with no effect it looks like a pump/ injector, or timing problem? A long shot, but maybe some debris got into the pump or injectors during re-assembly?

Paul T
 

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Discussion Starter #8
Thanks Paul. Could you or maybe someone else help me identify my IP. And I would like to know details about what rebuilt parts kit it takes.

This is an inline mechanical PFR type, three cylinder for a marine propulsion engine. From pictures I've seen, it looks like it could be a Denso or Zexel. I'm not knowledgeable on IP's. The engine is a Westerbeke 30B Three for propulsion (the engine is also used for gensets).

The numbers on the IP top are U 094500-451011S. I'm not sure about the "U" -- could be something else.

Thanks
Len
 

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Len,

My experience was with Bosch injector pumps so I am not much help on your request. Maybe Westerbeke could help? As mentioned earlier, perhaps another shop could look at them or maybe a Westerbeke dealer. I think it might be somewhat difficult to re-build or inspect for proper specs on your own. As I remember looking at a parts diagram there is a whole lot going on in there.

Paul T
 
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