Urgent help - nearly broke down at sea. Fuel Problem.

[Rake722]

Hi all, the urgency surrounding my issue is that our boat is in Greece which has little or no off shore support.
The boat is safely at anchor on a small beach and the issue we experienced needs fixing ASAP as we fly back in 4 days and need to get the boat to a permanent mooring within this time.

the boat - 1850 Capri 1994 with a mercruiser 3.0lx fitted.

The problem - all was going well coming back from another island when all of a sudden there was a distinct power loss and we went down to 5 mph at WOT position and 3k rpm. We managed to get to our anchor like this. I was too afraid to back off the throttle until we got to the bay where our anchor is. I then brought her to idle and approached buoy and anchored.

I thought we had run out of fuel so added 20 l to the rank from a Jerry can but when revving out of gear I could tell the issue was still present.

I then undid the fuel filter / water separator type to find very little fuel in it.

this lead me to suspect the fuel pump or anti siphon valve.
Is there any way to check the valve ? I have limited tools here.

I believe it could also be a blocked fuel pickup in the tank.

I don’t have access to a remote tank to test this with.

many ideas welcome. I’m also investigating getting a tow but it’s not easy here. It’s quite remote.

many thanks in advance

 

[Scott Danforth]

anti siphon valve can be tested by blowing in one direction or not in the other

fuel pickup tube could be removed and check to see if there is a filter element in it.

did you check to see if your vent line is plugged? simply open the fuel cap, if it hisses, most likely the vent line is plugged.

however in an emergency, pull the hose off the anti-siphon valve, remove the fuel sender from the tank. stick the hose in the tank and see if that works.

someone will have to hold it there as you do not want to leave open fuel system or the hose flopping around. however that would allow you to get the boat to the dock

 

[Rake722]

anti siphon valve can be tested by blowing in one direction or not in the other

fuel pickup tube could be removed and check to see if there is a filter element in it.

did you check to see if your vent line is plugged? simply open the fuel cap, if it hisses, most likely the vent line is plugged.

however in an emergency, pull the hose off the anti-siphon valve, remove the fuel sender from the tank. stick the hose in the tank and see if that works.

someone will have to hold it there as you do not want to leave open fuel system or the hose flopping around. however that would allow you to get the boat to the dock

Thanks for the speedy reply.
Checked for vacuum in the tank - not present.
No hiss when opening the fuel filler slowly.

as for the test of the anti siphon valve, I take it that for a correctly working one blowing tank to pump direction should be open but pump to tank should be closed ?

dock is 4 miles away over open sea. I’m not sure that holding the hose in the sender hole is an option as it’s not a flat lake. I don’t even think the hose is long enough to reach although if it did it could prove the valve and I could possibly remove the ball bearing and spring to get to dock.

the pickup - how likely is it to be blocked ? I’ve rebuilt engines but have not yet worked with fuel tank systems. Is it on the tank side of the anti siphon valve? How could I check it ?

in tandem working on getting a tow to dock but nothing yet on that one.

thanks again

 

[Scott Danforth]

got a bucket, you may be siphoning fuel to a bucket if your hose is not long enough.

pickup tube unscrews and comes straight up. I know in my boat, I do not have room to unscrew in the boat. I would have to pull the motor to be able to pull the tank to be able to unscrew the pickup tube. or I need to cut a big hole in the deck as the pickup is about 250mm away from the inspection opening over the sender.

 

[Rake722]

Ok so I took the ASV out and blew in the direction of flow to the pump and there was restricted flow indicating the problem.

I then bashed out the collar ball bearing and spring and replaced it free flowing. I then started the boat and she seemed to run a lot better. Revved as normal.

I checked the fuel filter and there was about 3/4 full of fuel as opposed to almost empty.

I have yet to pluck up the courage to test it under load as we are alone and it’s open sea as opposed to a lake.

we have arranged to be towed to dock by a local fisherman tomorrow. His vessel is a Greek traditional fishing boat.

this is now time critical as we fly back Monday 30th and it’s now the 26th

 

[Rick Stephens]

A partially empty filter could mean you have a loose connection or a small hole and are sucking air.

 

[Rake722]

A partially empty filter could mean you have a loose connection or a small hole and are sucking air.

True but after removing the ball bearing and spring from the asv the filter seems full again. Well 3/4 full as opposed to near empty. I take it they shouldn’t be full to the top.

 

[Rake722]

Ok plucked you the courage to test it with the check ball removed from the asv. Was fine for 5 mins then the same issue again. Returned to anchor at fast idle.
Checked all hoses - no issues.

stumoed

 

[kenny nunez]

Good possibility that the screen in the suction tube is where the problem is.
Hopefully you will be able to unscrew the fitting from the tank, the tube screws into the 90* fitting so that you push the screen out with a suitable tool.

 

[Eric 3.7LX Alpha 1]

Sounds like you haven't checked yet for an obstructed pick up. BTDoctur had a post recently where he found blocked inline filter in the tank pick up.

Edit: here is his post: https://forums.iboats.com/threads/f...-but-may-apply-to-all-installed-tanks.749555/

 

[Rake722]

Sounds like you haven't checked yet for an obstructed pick up. BTDoctur had a post recently where he found blocked inline filter in the tank pick up.

Edit: here is his post: https://forums.iboats.com/threads/f...-but-may-apply-to-all-installed-tanks.749555/

Yep thought about it after posting. I tried to get the big top nut undone today with an adjustable spanner to no avail.

was I working on the right nut or should I be undoing the square block that the asv screws in to ?

 

[Eric 3.7LX Alpha 1]

I'm not sure what your setup looks like. Take a photo of it so we can see what you have.

 

[johnkom]

Am I missing something?

"...went down to 5 mph at WOT position and 3k rpm. We managed to get to our anchor like this. I was too afraid to back off the throttle until we got to the bay where our anchor is. I then brought her to idle..."

That doesn't sound like fuel to me. Sounds like a spun coupler.

 

[AShipShow]

Had the same thought, but 3k at WOT is also not correct... If it was a spun coupler and you went full throttle, you'd rev way above 3k...
Still, 3k rpm and 5mph doesn't add up either, but usually if you spin a coupler, you'll have zero power until you stop the engine for a minute and let the coupler resolidify and you can usually idle back to the dock.

 

[Rake722]

Regarding a spun coupler - I’ll explain more clearly what happened.

we were cruising at 3600 rpm or thereabouts at 23 mph with 4 young kids and 2 adults. All of a sudden the rpm dropped to 3k on the gauge and we lost power and slowed down to around 5-10 mph maybe more but my gauge isn’t working and I was too busy thinking to get the gps reading from my phone. I then pushed the accelerator to WOT position but the tachometer stayed at 3k rpm and had no effect on power - still way low. When we got to the bay where our anchor is I backed off the throttle to neutral and then forward at 1000 rpm to get to our anchor.

so moving the throttle to WOT didn’t increase the rpm or speed of the vessel but we were able to idle to anchor.

I would have thought that the lack of fuel in the filter surely points to fuel starvation ?

the same happened today. Ran fine for 5 mins after removing the check ball from the asv but then had the same issue and again little or no fuel in the filter / separator

 

[Bondo]

Ayuh,....... Use yer wrench to hold the big nut you couldn't move, 'n with another wrench, turn out the elbow the asv was screwed into,.....
If yer lucky, the dip-tube will come out, with that elbow,.....
If not, atleast you'll have a straight shot at roddin' out the dip-tube,......

 

[Rake722]

Ayuh,....... Use yer wrench to hold the big nut you couldn't move, 'n with another wrench, turn out the elbow the asv was screwed into,.....
If yer lucky, the dip-tube will come out, with that elbow,.....
If not, atleast you'll have a straight shot at roddin' out the dip-tube,......

Thanks Bondo, we ran out of time and the boat is due to be towed to dock in an hour or so. Now she will be at the mercy of Greek island engineers.
Not ideal

 

[Rake722]

Had a quick go at removing the pickup tube but the fitting wouldn’t budge. Don’t want to risk breaking it and don’t have time for penetrating fluid.
I found a local with an outboard tank and I hooked it up directly to the fuel pump. Started her up at anchor in neutral and brought the rpm to 3500 and it bogged down.

connected the tank again and it did the same.

as we weren’t under load I can’t tell for sure but it sounds like the issue exists when using another tank - I take it could either be the fuel pump or carb ? We hooked a vacuum pump to the pump inlet and gave it 5 psi vacuum and it held vacuum well. We then connected it to the hose from the tank to filter and it also held up well so no air leaks and diaphragm seems ok on the pump

am I on the right Track here ?

many thanks

 

[AShipShow]

Have you confirmed that the choke is working properly?? after running for 5 minutes, the choke should be fully open, maybe its stuck closed and thats causing the engine to starve for air..

 

[Scott Danforth]

We hooked a vacuum pump to the pump inlet and gave it 5 psi vacuum and it held vacuum well.

the tanks are externally vented. they should not hold vacuum at all.