Engine stopped and I am Stumped

DDD

DDD

New Member
Oct 27, 2012
268
Tampa, FL
Boat Info
2008 45
Engines
Diesel
2008 Sundancer 330
V-Drives, Merc 8.1S Horizon.
DTS
175 hrs on each.

Was cruising around, but doing a lot of idling watching a boat parade.
Starboard engine just turned off, and would not start up again.
--Plenty of Ethanol-free gas.
--Battery was at about 12 or 13 Volts.
--Generator still ran.
--Water pump was still spitting our water.
--Oil pressure was normal.
--Temp was normal.
--Would not start with "emergency battery" start.
--No alarms or warnings on the SmartCraft.

After about 30 min, and intermittently a few failed attempts, it started again.
Cruised around without any problems.

Was at an area where we were watching a parade again- idling. And it did the same thing again.
After about 30 min, started again.

I put a volt meter on the batteries-- 14 + at rest, 13+ with engine (alternator) running.

:huh:
Any thoughts on what it could be?
Any next steps to trouble shoot?
:smt021 Argh!
Thanks for helping-- my brain is fried trying to figure this out.
 
That sound like what I had - vapour lock due to the Fuel Cooler.

Salt water is used to cool the fuel via the fuel cooler - and when you get to much "growth" in that - the fuel can get to hot - creating air pockets that block fuel from flowing to the engine. The symptom will usually start to show when in idle since fuel flow is slow. If you run at higher RPMs it will usually not show.

So get your fuel coolers flushed out with acid (better yet - do the whole raw water part) - and if the fuel cooler is not rusted - that should take care of the problem.

I guess you might not have flushed your engines after use? My boats PO never flushed and I had vapour lock in both starboard engine and the generator.... My water flow through the fuel cooler was only 10% of "specification"....
 
Sounds like a similar problem!
Here's a novice question:
How do you flush your fuel coolers?
 
DDD said:
Sounds like a similar problem!
Here's a novice question:
How do you flush your fuel coolers?
Click to expand...

I had my mechanic do it. It is not easy access. Alternatively you can fill you cooling (raw water part) system with Barnacle Buster. That requires a bit of engineering. But if yours is as mine was - very little barnacle buster will reach the fuel cooler.

So best option is taking it off. You might have the same fuel cooler as I have - (2008) - so the water hoses are not easy to get to without taking the cooler out. Then you can attaches a acid safe pump to the inlet/outlet and circulate Barnacle Buster through until flow volume is back up to where it is supposed to be.
 
Anyone know what the fuel cooler looks like?
I can not find it on the parts catalog on the Merc website.
 
DDD said:
Anyone know what the fuel cooler looks like?
I can not find it on the parts catalog on the Merc website.
Click to expand...

The fuel cooler is the fuel/pump/filter/cooler in one. So find your fuel filter :) and you have found the cooler.

If you face the heat exchanger - it is the lowest part down to the left. A big "boxy" bolt on - and on the top is the fuel filter secured with 3 bolts. The fuel filter is a "pull up" filter where you loosen the bolts and pull the filter upwards.

here is a link for a similar model : http://www.ebay.com/itm/Mercruiser-..._Accessories_Gear&hash=item53f3cba444&vxp=mtr
 
Thanks!
I wonder if an old fuel filter could slow the fuel flow enough to cause a vapor lock...
 
DDD said:
Thanks!
I wonder if an old fuel filter could slow the fuel flow enough to cause a vapor lock...
Click to expand...

I would not think so. Then you are likely to have issues throughout the RPM range and unstable idle. But the filter should be changed every year anyway. My boat was from the same area you are in - and the volume of growth in the cooling system was very high - and all due to PO not flushing after use. It is SOOO easy to do - and still not done once in 4 years.
 
kaz911 said:
I would not think so. Then you are likely to have issues throughout the RPM range and unstable idle. But the filter should be changed every year anyway. My boat was from the same area you are in - and the volume of growth in the cooling system was very high - and all due to PO not flushing after use. It is SOOO easy to do - and still not done once in 4 years.
Click to expand...

You flush the cooling system after each use?
I am missing something...
How do you do that?
My boat is in the water all of the time
 
DDD said:
You flush the cooling system after each use?
I am missing something...
How do you do that?
My boat is in the water all of the time
Click to expand...

If you engines are Horizon engines - I think you might have a fresh water flush port? Usually mounted on the starboard riser. On SeaCore engines it has a "blue" plastic push in "cover" - but I'm not 100% on how it is on the inboards/horizon engines.

Then you just attached a hose to it while engine is off. Turn on fresh water supply for 20-30 seconds - then start engine and let it run for 10-15 min (until thermostats open and a bit after) - then turn engine off - and leaver water running for 10 seconds - and turn fresh water supply off.

If you do NOT have flush ports - get them installed. They are quite inexpensive and will save you a lot of money in the long run if you use them.

You do not need to flush every time you use the boat. But I would flush every time I know the boat will be not operating for more than a week. You can also add "Salt-Away" to the flushing water - which can help loosen up "old salt" - but it will not help do a "complete" clean (as when you have problems already.)

But if your fuel cooler is "gunk'ed up" then it is also likely your heat exchanger is. The heat exchanger is quite happy to be flushed as well.
 
To quote the Mercuiser Horizon Manual "If operating in salt, brackish or polluted waters, flush cooling system after each use." (pg 39)

http://www.*******.com/merc/Owner/gas/86135703.pdf

Page 61 - flushing instructions - they are DIFFERENT from SeaCore engines - so please use the instructions in your engine manual!

I flush about once pr. week but use Salt-Away after "normal" flush.
 
Last edited:
Here's something to try...

With the engine hatch open, turn the ignition "ON" for the good engine and listen for the fuel pumps buzzing sound. Do the same routine for the problem engine. If the sound is either very different or worse, there is no buzzing at all, you might want to take a good look at the two electric fuel pumps. One is for high flow, the other for high pressure.
 
Was there any form of alarm? I posted yesterday on another thread about a solid alarm sound that we have had 3-4 times, but almost always after we have been idling or trickling around (courtesy of the speed laws in Western Australia) - now I'm wondering if we could have a similar problem, our boat has been in the water since July and not flushed once. I didn't even know you could. It's always worried me (previous boat was on a trailer and all this was a breeze). Now I'm excited to here it might be possible and want to go check it out - dammit, have to work today......
 
Giles91 said:
Was there any form of alarm? I posted yesterday on another thread about a solid alarm sound that we have had 3-4 times, but almost always after we have been idling or trickling around (courtesy of the speed laws in Western Australia) - now I'm wondering if we could have a similar problem, our boat has been in the water since July and not flushed once. I didn't even know you could. It's always worried me (previous boat was on a trailer and all this was a breeze). Now I'm excited to here it might be possible and want to go check it out - dammit, have to work today......
Click to expand...

With vapour lock you do not get an alarm usually. But alarm in idle can be a lot of things. Do you not have smart craft instruments? They show the alarms in "clear descriptive text" if you press the right button on it :grin: My friend just had alarm due to the gear neutral switch was broken - gave alarm in neutral and slow forward/reverse - and engine could stall out. If you do not have smartcraft - then get a Merc NMEA 2k gateway ($368) - then engine alarms will show on your Simrad GPS/Sounder.
 
New info...
Motor ran great at idle, low RPM, high RMP.
I turned on the generator, and the motor died instantly.
Shut off generator, and it would not restart.
Let it rest for 30 min.
Throttled up the working engine, and restarted the non-working.
Ran fine again.
Docked. Then restarted without a problem (without the generator).

Definitely associated with turning on the generator. But is it fuel, electrical, or something I did in a prior life to deserve this?
 
What was the eventual outcome of this? I am having a similar issue on my 2006 340DA with 8.1Ls. (Not related to the generator from what I can tell, it has been off during these issues).

This is happening on my port engine. Runs fine at higher RPMs. While idling around and at low RPMs it stalled out and would not start for 30min or so. Had to come home on one engine. Just sitting in the slip today it started cold, ran for 15min or so, died and would not start up. Waited about 30min and it would start up again and eventually die. No alarms.

My mechanic was able to take a quick look at it and thought the pump was intermittently not supplying fuel pressure. This is new to me and I was not aware of the cool fuel issue at the time. Would the vapor lock you described above cause an intermittent drop in the fuel pressure line or is it something that would cut off pressure internally in the engine?

I've read similar symptoms happen on a leaking fuel injector eventually flooding the engine at low RPMs, but having no pressure in the line seems like a different issue. Curious if the fuel pump replacement fixed your problem.

Thx.
 
Just found this thread from 2013. I'm having same issue.
‘02 Sea Ray 380 with twin 8.1 horizons. 650 hours.
Symptom: After running for about 2 hours at cruising rpm, in moderate chop, my port engine acts like it wants to stall out and won't maintain RPM's. It doesn't actually stall, but the engine won’t run much higher than idle rpm. If I shut the engine down for 5 min or so it fires up and will run fine for another 10 or 15 min. Then it happens again. It happened to me 3 times last season on long cruising runs of 2+ hours.

Originally we thought it might be water in fuel, but no evidence of moisture in filter and our last fuel sample draw had no evidence of water. A mechanic suggested it might be the fuel pump overheating and not pumping adequate fuel to maintain RPM’s. Looking for opinions or solutions. Thanks.
 
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