BMC 1.8 Starter/Staring Problems

[john.k]

This is the boat with 4 yr old batteries......the cells may have sulfated and have high internal resistance....or may have lost a lot of active material from deep discharge cycles............does anyone remember the high rate discharge testers ..........that look like some antique sci fi weapon......well ,thats whats needed.

[Tony Brooks]

4 hours ago, john.k said:

This is the boat with 4 yr old batteries......the cells may have sulfated and have high internal resistance....or may have lost a lot of active material from deep discharge cycles............does anyone remember the high rate discharge testers ..........that look like some antique sci fi weapon......well ,thats whats needed.

agreed, but one that has the correct discharge for the battery, a car one may well not give a meaningful reading, and the batteries would need disconnecting from each other. However the cranking voltage at the batteries and then the motor would do almost as well.

[Puff Along]

On 20/04/2022 at 18:29, Tony Brooks said:

Just the heaters should not drop the battery voltage to 10V. The starter load will, but not the heaters. Modern heaters tend to draw a very high current quickly dropping to about 50 amps total for all four plugs. That 10V makes me suspect a battery problem or resistance in cables, but not the glow plug cable. Either in the negatives or between battery positive and wherever the voltmeter is connected.  If you are using a voltmeter on a glow plug then it could be a cable or switch problem but that does not square with the low cranking speed unless the problem is in the master switch.

 

[Puff Along]

Right here we go!!! After 6 hours of bleeding ,cutting out .We had to revert to the dreaded easy start to get her to fire up We believe the New Injection Pump is faulty!!! I say new it was brand new [not a recon ] 8 months ago and  it has done less than 20 hrs .Well I say we it should be Martin he got it running for 15 mins .Then it started hunting rvs up/down exactly what it did 4 weeks ago 7 miles out at Sea and I limped it back into the bay ,where I fished all day and it started stopped all good but I never to it over 5 Knots..I did this as I have a outboard for such cases.

I believed the fuel was compromised with diesel bug .{Bit I always use diesel bug inhibitor]  I remembered on my last engine it had a bad case of bug and the engine note sounded exactly the same. When I changed the filters they where clean the separator bowl had less than .5''of water in it. 

We checked and checked again the for air one the connections,Bleeding the bleed screws and injectors as we went.Martin Heated the heater plugs direct from a 115 amp starting battery,You name it he did it.

Once started it will run ok then hunt it may pick the revs /then decrease up 2/3 times then cut out completely .It may run hunt then cut out, it is Very Random.

I will put on a video [it may take a minute as it is on my phone not on the lap top yet] where you can hear the different engine notes but I couldn't catch the actual stalling of the engine on video.

PS the Batteries are NOT Leisure as I said they are starting Batteries by Hancook XV110 MF   Made July 2018 

[Puff Along]

On 20/04/2022 at 18:29, Tony Brooks said:

Just the heaters should not drop the battery voltage to 10V. The starter load will, but not the heaters. Modern heaters tend to draw a very high current quickly dropping to about 50 amps total for all four plugs. That 10V makes me suspect a battery problem or resistance in cables, but not the glow plug cable. Either in the negatives or between battery positive and wherever the voltmeter is connected.  If you are using a voltmeter on a glow plug then it could be a cable or switch problem but that does not square with the low cranking speed unless the problem is in the master switch.

 

[Tony Brooks]

When BMC 1.X start to suffer fuel starvation they do tend to rev up so if something is causing intermittent fuel starvation it would sound like hunting.

[Puff Along]

How do I put on a video of the engine hu ting 1min30secs

Would be a Pump Problem 🤔?

[Tracy D'arth]

You have fuel starvation.  Classic symptoms.

What's the tank pick up like? Diesel bug will block pipes never mind filters. What about the lift pump?  And the filter in it under the dome?

 

Get a gallon can of clean fuel and pipe the pump into that, remembering that the return will need to be in the can too. Run the engine and see what happens. It is highly unlikely the injection pump that is faulty.

 

Edited April 22, 2022 by Tracy D'arth

[Tracy D'arth]

I have sent you a PM

[Puff Along]

1 hour ago, Puff Along said:

I have the cables to go in beefy 50mm ones

 

 

[john.k]

i have never had diesel bug survive the biocide ......if filters arent blocked ,then I doubt it is that.(assuming filters have been disected  to check).........I mentioned some time ago of problems caused by a small piece of rag in the tank..................and as mentioned,fuel starvation causes a DPA hydraulically governed pump to rev ,then cut out..............one time I saw an incrdible blockup caused by a small insect that filled a syphon hose with small leaves from a plant in the boaties garden......Tiny leathery leaves that blocked pipes and tank fittings...........the funny thing was the same blockup happened again ,because the boatie didnt check a syphon hose ,and put the leaves into the tank a second time.

[Puff Along]

Cheers John very little evidence of contamination in the 2 filters that where replaced.I will leave it alone for a couple of days ,Go back with a clear mind. Digest the thoughts of the members and work through it all again. But I will renew the fuel line from tank to engine.It is partly old rubber and copper.The mechanic has some Lloyd's Fuel Line in his garage so we will install that. Then start over.

Thanks to everyone for their time and thoughts, I'm away for the month of May in the US as my Granddaughter is graduating from College. Might be able to get a couple of Steelhead an Coho Salmon as well!