Detroit 8v71s cleaning fuel at idle or hull speed

[tomrealest]

My 46 has been on the hard since December 2013. How long do you think it would take to "polish" the fuel? Belly tank is full but the saddle tanks are only 3/8's full. I have been running them at the dock with the saddle tanks for 3 hours now. Revved them up to 1200 rims half hour ago.

Thoughts?

[Boatsb]

The crud settles. You need to shake it up to get it clear. Additives will fix things if you know what they are. If you have algae add an algicide like ajx that clears the debris. If not just add a cetane and lube like optilube summer plus.

[Dan Mapes]

If you take it out to shake it up bring a couple of sets of filters and run the engines on different tanks. Perhaps one on the belly and one on a saddle. Keep an eye on the filter bowls for crud settling.

[bobk]

If you take it out to shake it up bring a couple of sets of filters and run the engines on different tanks. Perhaps one on the belly and one on a saddle. Keep an eye on the filter bowls for crud settling.

Better yet, put vacuum gages on the Racors and you'll know when you need to change them. I agree, you need to shake the tanks up to stir up the sludge. It may take reducing the level in the full tank to get it to shake.

Bobk

[Glory]

Tom,

Hope thing are well.

When the PO handed over my YF he told me the fuel in the rear tank had been in there for 10 years.

I was going to have it pumped out, when I removed the fuel gauge in prep for the pump truck I discovered baffles. And I thought it un likely the "bad stuff" would all be removed, if any. So I canceled the pump truck and went out on a windy day, 20 knots, and motored around at all points of the compass. First filter alarm in 20 minutes second in an hour. Then I just used the up switching back to the center and forward tanks when losing an engine would be bad.

Back then the fuel value was only about $600, pump truck was going to be $200.

On the second tank of fuel only one filter change extra compared to the other engine. I rarely run both engines on the same tank, I treat each time I fuel.

JM

[Dan Mapes]

I am thinking that if you shock the tank with biobore or something similar you can expect a mess of goo in your filters.

I would hold off on additives until after the shake down. Then I would use them and be ready for another mess of filter changes. If you can get a good price on a dockside polish it might be worthwhile.