Etec 50hp (2007) rough idle and stalls, runs fine at rpm and under load [ Edited ]

[stickycode]

Hi,

I was told the #1 injector was the problem and I think it was problematic but its been replace with zero change in behaviour.

New plugs indexed correctly

New #1 injector

TPS has been replaced

Compression is good

spark is good

replaced throttle and control cables

no alarms or codes after the #1 injector and TPS replaced

Its been suggested that the #2 injector could be dirty and its runs OK because of the higher pressure fuel under load is pushing past the dirt. 

After the above work it did idle smoothly for 5 minutes, then put it under load > 3000RPM in forward for a minute and it was back to rough idling.

The only other thing is that the battery is not in great condition, is it possible that the battery load is dragging the voltage down and interupt correct operation of the EMM?

Any suggestions appreciated.

Michael

[Nordmann]

Exhaust filter, Champion plugs, engine report?

[stickycode]

Yes new champion QC12PEPB plugs properly indexed. The experts did it, I'm assuming can double check but it made no difference.

 The engines are E50DPLSUM 05/2007 (starboard) and 03/2007 (port)

IIRC the exhaust filters were pretty shot at least I was shown the port one, I'm waiting for the itemisation to know exactly what was replaced during the service.

The enginre report was clean, but I will get a copy.

[stickycode]

The batteries are not in great shape and it would seem from my internet research [1] that > 800MCA is recommended. They are underspec'd at only 580 MCA (460 CCA). I'm in Auckland NZ and the weather is relatively mild.

For a low HP motor requiring 800 MCA seems extreme, I'm assuming that voltage drop on the EMM is an issue.

This is a house boat and the cable runs are 6-8 from engine to battery. 

I'm going to attach a jump pack to the starter to rule out cabling and battery issues as being a cause of the rough idle/stall

[1] See http://www.dekabatteries.com/assets/base/0406MarineApplicationslayout.pdf

[stickycode]

The fuel filter in the pump and in the high pressure fuel system were blocked, clearing them out made a big difference no more stalling. 

Seems like #2 injector might be playing up, obviously was a bit a crud in the system. The idle is still rough but a lot better.

Going though a process of fuel conditioners and enginer tuner sprays to clean out the engine to improve the idle. The power is obviously much better now too.

[Nordmann]

In post #3 you mentioned 'the experts did it'. Did'nt they clean out the VST filter and HP pump filter?

Injectors can be cleaned reasonably well by dismantling them and removing the nozzle and screen. Requires special tools which I hope your experts have.