Fuel starvation one engine

D

drfeno

Member
Joined
Jun 19, 2008
RO Number
30284
Messages
133
Hello all,

I have a 1981 silverton 31 c that just recently had an issue while out at sea the other day. while at cruise, my port engine began to sputter and over the next few seconds, stalled completely. I was able to restart it, but it sputtered and stalled again in a minute or so. then it became unable to start. It seemed like a fuel issue, so as a last resort, I opened the crossover valve between the 2 tanks, and the engine was able to start, and ran fine for the remaining hour ride to port. This tells me that the fuel system on the port engine is fine from at least the water separator to the carb. I would think that there must be an issue with the fuel pickup tube on that tank. Perhaps a clog at the end, or something clogging it. I want to pull the tube and inspect it, and or replace some pieces. Has anyone had this happen to them?

Thanks
 
How about a bad anti-symphony valve on the tank of the affected side, or a clogged fuel line ent? You can check the vent by opening up the fuel fill cap and see if she runs.
 
What Greg said. I would definitely close the crossover and try running with that fill cap off as suggested to easily check whether it is a vent issue 1st.

You mentioned opening the crossover but not closing the port tank valve.

If port tank shutoff was left open and it then ran fine, it shouldn't be a porous or broken pickup tube issue ( both engine would likely suck air) though the pickup sock could be clogged or vent clogged or as Greg also suggests a clog in the "anti-symphony: valve.

If the port tank shutoff was closed , are you sure fuel in the port tank isn't just below normal min. usable level? Does the port tank feed a generator?.

....Probably.... not phase-separated gas issue in the port tank as that would likely have affected the port filter.

Almost surely not a fuel pump or ignition issue which coincidentally cleared itself up.

It sounds like with crossover open, the stbd tank feeds both engines through their own filters, which rules out clogged filter.
 
Thanks all, I’m traveling in Poland with very spotty cell coverage. I didn’t shut the port tank valve, I was just happy it started running being out to sea near a crowded inlet. I kind of doubt it’s a vent issue sinc it ran fine for hours then just decided to quit all at once, but I’ll check that. There’s no way I’m not pulling the dip tube just for my own piece of mind. I do pretty much know that all components down stream of the crossover are ok, including the water separators and fuel pump. After opening the crossover the boat ran perfectly for the next hour.
 
blow out the fuel line after checking all the filters
 
You've isolated it to one of the three if it's a fuel issue.
 
On my new to me 1989 vintage boat back several years ago, I had a problem with crap in the tank collecting in the anti-siphon valve. When I first pulled the dip tube and discovered there was no screen/strainer at the end, I then checked the AS valve and discovered my problem. The AS valve was acting as a strainer and collecting the crap in the tank until it was full of it. After fabricating a dip tube screen/strainer, my problem went away.
 
I’m not familiar with anti siphon valves as it applies to fuel systems. Is it located on the shutoff valve on the top of the tank? I’ll research it a little. Thanks again.
 
I sucked up crap from my tank. It got into the filter and totally clogged the intake.
I had changed filter but that didn't work until I removed the filter bracket and saw this black crap stuck in the inlet side.
Cleaned that out and it ran fine, but I went one step further and had both tanks polished.
Was only $400 and the guy sucked both tanks dry and got all that crap out of the tanks.
Then pumped back my fuel.
This was diesel.
 
The AS valve should be located at the tank top fitting. It is basically a check valve that can be unscrewed from the tank top fitting. Mine was clogged with what looked like fiberglass strands even though my tanks were aluminum.
 
Thanks, I’m away until the end of next week. I’ll disassemble it when I get back and see what I find.
 
That's what mine looked like it was clogged with fiberglass or wood shards from drilling a hole.
I think when these boat builders build these boats that are not very careful with crap. I find all sorts of sawdust, nails, washers, etc all over the boat. But its not different with a home, I go in my attic and find crap too that shouldn't be there.

Again, I think having the tanks polished for $400 was money well spent because now I know the only thing in my aluminum tanks is fuel!
 
My tanks are quite old, going on 40 Year’s. I’ll look into tank polishing, but probably not this season. Realistically with kids and school, we only have about 6 weeks left. I’m actually worried a little about my tanks given Their age. They appear fine from the outside but that doesn’t mean much,
 
Update:

Thanks everyone for all the input. It turned out to be the anti-siphon valves. Both were packed with crap, little bits of rubber and wood and spiral metal shavings that look like drill shavings. From the look of them, I'm surprised both engines could run off of the one they did. Both of the ball check valves were pushed and held back by the debris, so they weren't even working as anti-siphon valves anymore. The geometry of my tanks doesn't allow me to remove the dip tubes without destroying them or my salon floor. I will say looking at the size of some of the debris, there is no screen on the end of either of the tubes at least not anymore. I did blow out the lines from the top of the dip tubes back into the tanks, and the line from the anti siphon valves to the crossover tie in. I also checked the inlet of the water separators, both were clear. seems a crazy design to have the anti siphon valve be the first device to encounter crap. Maybe there were screens at the dip tube ends. Not this season, but maybe a filter should be installed before the anti-siphon valve. It would be higher than the top of the tank, so even if it failed, no siphon would occur.
 
Thanks for the follow up and glad that you found the problem. Good to go for another 37 years.
 
You must log in or register to reply here.
Back
Top