Mercruiser 3.0 Chronic Fuel Quality Issues

[CPro]

Hey guys,

I've had continual fuel quality problems this summer with my 1997 Mercruiser 3.0LX in my 1997 Sea Pro 19' walkaround.

I had problems about a month ago with water in the gas, which I resolved by draining the tank, etc..

I ran the boat about a week ago..and it ran but wanted to stall at below about 1000 RPM's. I went out and got a new fuel filter (the inline one that goes on the carb) and installed that last night. I took the boat down, launched it, and she was running very rough. I could get it started, but the only way it would keep running is if I kept "gunning" it up to about 2000 RPM.

The plugs looked OK, a little bit darker than I'd like, but not too bad. I drained some gas and there is no noticeable water in the fuel.

The fuel filter, however, after running just that little bit of time already had a good collection of crud! When wet, it looks like little grains of sand. When it dries out, it looks more crusty. Is this some latent effect of having water in the gas a month ago? Or is this particulate stuff a result of gunk coming out of the gas tank due to ethanol in the gas? I'm thinking that this gunk is probably the reason that I was having problems?

Here's a pic of the dried up stuff in the fuel filter (from roughly 1 hr of fiddling with the boat).

If anyone can give me any leads as to how to get rid of this curd, and how to avoid this stuff in the future I would greatly appreciate it! I already cleaned the carb out this morning...there was definitely some crud in the float bowl.

Thanks as always,
Trev

 

[tommays]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

There is a good chance that the filter in the fuel pump is breaking down the older ones were a stone (at least in 1995)

I would also install a full size spin on filter before the fuel pump to collect junk and water


Tommays

 

[CPro]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

It's a brand new fuel pump...so I'm hoping that is not the case.

I'm thinking this could be due to the ethanol in the gas? I really had no problems last year...this year it has been a pain in the butt..!

 

[Don S]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

Do you have a water seperating fuel filter installed between the tank and the fuel pump????? If not, better get one.
Might also want to check the tank for water again. If you have a bad seal on the gas cap or a vent getting water in it, that could cause more water.

 

[johnbo]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

One thought, do you know how the water got into the tank when it first happened? My buddy, who got me into boating, had a '91 Reinell that had a passage under the steel fuel tank that apparently got filled with gunk and allowed the bilge water to eat at the fuel tank. A couple of years ago he started getting recurring problems with water in the gas, yet the fuel supply (local gas stations) weren't having troubles.

Eventually, it ate through the bottom of the tank and flooded the bilge with 30 gals of gas. The fact that he didn't notice the gas smell in his garage (with the furnace) that winter is another story.

Something to consider if you've got steel tanks.

Later,

johnbo

 

[CPro]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

I've got what appears to be a plastic tank. Water got in the gas a month or so ago due to the fact that I had not tightened up the fasteners on the fuel tank gasket enough...I washed the boat down and water pooled up on top of the tank and then dribbled in. There was a LOT of water in the tank at that point.

I'm going to try to drain some of the gas out of the tank today, we'll see how it works.

 

[Don S]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

Like I said before, put a water seperating fuel filter in the system, and it will keep the water out of the engine.

 

[CPro]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

Yep, I gotta do that (add the extra filter)

After cleaning the carb out & resetting the timing the boat is running very well again.

Thanks as always for your advice!

Trev

 

[pbon]

Re: Mercruiser 3.0 Chronic Fuel Quality Issues

Yep, I gotta do that (add the extra filter)

After cleaning the carb out & resetting the timing the boat is running very well again.

Thanks as always for your advice!

Trev

Everyone i know with a boat is having problems this year and i think it all has to do with Ethenol there is a prduct called Starton wich is supposed to help