Vetus M4/Mitsubishi S4L hard to start

[txg]

We have a Vetus M4.35 in our boat that was installed in 2015 and has run 700 hours now. It always started instantly (less than a second).

In August 2017 we put the boat in storage until some weeks ago. Before launching we did a full service (changed all the fluids and filters) and since then the motor takes about 8-10 seconds till it starts. Once it does, it runs perfectly fine.

The obvious solution here is an air leak from the service (filter not screwed in properly or something like that). But our engine has an electric priming pump and even when i let it run for about a minute before starting it still takes about 8-10 seconds.

We're always starting in idle, haven't tried starting with higher speed yet. Worked fine for hundreds of times before. The starter is revving fine, so it's not a bad battery or anything.

Any other ideas what could cause this problem?

[atoll]

on these engines the fuel pump is self bleeding so should quickly remove air in the system after a filter change.
if under load the engine runs rough then you might have an air leak.
could also be a sticky fuel shut off solenoid or bad connection or leaking o ring

could also be blocked fuel lines,again check with load on the engine for fuel starvation.

[atoll]

Originally Posted by atoll

on these engines the fuel pump is self bleeding so should quickly remove air in the system after a filter change.
if under load the engine runs rough then you might have an air leak.
could also be a sticky fuel shut off solenoid or bad connection or leaking o ring

could also be blocked fuel lines,again check with load on the engine for fuel starvation.

also,since the vessel was in storage it is possible there has been a loss in compression,due to corrosion on a couple of the valves or a stuck piston ring.

old dirty fuel might also cause problems,is the exhaust smokey.black or white

[txg]

Hi atoll, thanks for your reply. Once it started, the engine runs perfectly fine at all power settings. There are no leaks and it also stops without any problems.

On the first runs, the exhaust had a very small amount of white smoke, but that's gone now. The fuel is clean (polished it before first engine start), but we haven't refueled yet, so about half of it is from july 2017 and the other half from maybe april 2017.

I just tried starting it at a little bit more than idle, it started faster than at idle, but still took way longer than last year.

Next thing i will try is to put in some new fuel to make sure that's not the problem.

[atoll]

Originally Posted by txg

Hi atoll, thanks for your reply. Once it started, the engine runs perfectly fine at all power settings. There are no leaks and it also stops without any problems.

On the first runs, the exhaust had a very small amount of white smoke, but that's gone now. The fuel is clean (polished it before first engine start), but we haven't refueled yet, so about half of it is from july 2017 and the other half from maybe april 2017.

I just tried starting it at a little bit more than idle, it started faster than at idle, but still took way longer than last year.

Next thing i will try is to put in some new fuel to make sure that's not the problem.

is there a heater element in the air intake that might not be functioning,i don't think these engines have glow plugs?

partially blocked exhaust? soot in exhaust at high revs under load would indicate this.

billowy white smoke generally indicates water in the fuel.

worn injectors,how long since the were last serviced

[txg]

Thanks for the question about the glow plugs. The motor does have these, and i can see on the battery monitor that the engine is not pulling the about 30amps it pulled before when putting on the glow plugs.

Maybe we accidentally took of a cable while doing the service, will investigate that now.

[txg]

I found out that i can measure 13,8V at the glow plugs when putting the switch in the glow position, but there is no current flowing. So the relay and the control circuit are working fine.

This means that all four(!) glow plugs have died, probably nearly at the same time, and just from sitting around on the hard. Doesn't make much sense to me. Is it normal behaviour for these to fail at the same time?

[atoll]

Originally Posted by txg

I found out that i can measure 13,8V at the glow plugs when putting the switch in the glow position, but there is no current flowing. So the relay and the control circuit are working fine.

This means that all four(!) glow plugs have died, probably nearly at the same time, and just from sitting around on the hard. Doesn't make much sense to me. Is it normal behaviour for these to fail at the same time?

that would explain the poor starting on compression only!
seems strange they have all failed at the same time,maybe check the connections before pulling the first plug.

i checked the manual,but could not see any reference to glowplugs in the parts list,so did not mention it in the first post!
as this was the first thing i suspected,perhaps the relay is still faulty with partially burned contacts

[Snowpetrel]

Sometimes Glowplugs are wired in series. Failure of one means they all die. Like cheap xmas lights.

[jimbunyard]

Don't forget to check all your grounds, especially hi amp ones. Does the engine seem to turn over more slowly than it used to?

[sailah]

I have same Mitsubishi S4L2 block in my Westerbeke 44B.

All 4 of my glow plugs failed at once. You can check them with DMM by measuring resistance from terminal to body. Functioning is 0.55 ohms. All mine failed but my engine still started OK.

I found the Factory Mitsubishi service manual in searchable PDF to be vastly superior to anything from Westerbeke. It also helps with finding factory parts so you can find inexpensive components. Let me know and I can send it to you although it's findable on web

I bought 4 new glow plugs for mine from Amazon PN: NGK (6528) Y114T Glow Plug, Pack of 1

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[txg]

I topped up the tank with 20L of fresh fuel and the engine is now starting faster, even without the glow plugs. Looks like we should do some motoring in the near future to get rid of the old fuel...

Regarding the glow plugs, i do have the following idea why they all failed:

After we did our service, i put the engine on preheat for about 30s (maybe 40s). I did this to fill the filters with fuel by the electric fuel pump without having to listen to the extremely loud alarm beeper that goes off when the engine switch is in the on position without the engine running.

The manual states that you should never preheat more than 60s, which i definitely did not do. But my guess is that the problem came up because we did this with shore power attached. We have a 55amp charger and this means the preheating was done at 14,4V instead of about 12V which increases heat quite a lot because of P = U² / R.

So now on to source these plugs on Grenada...is there any possibility these are used in Mitsubishi cars as well? Plenty of those on the island.