Gas In Water Separator 170 Osprey

[actualcivil]

Hello beloved members

my boat was parked for north of a year. a few weeks ago i took it out for the first time. It did ok for a while and ran great at idle, no issues. Once i opened up the throttle it didnt like it and died. after a bit it would start back up and run great on idle, but again, not on full throttle (or really any significant load).

Mechanic drained the tank, put what he called "heat" in it. he also cleaned carbs and changed plugs. New gas, etc.

i tool the boat out, ran it for maybe 40 minutes. Ran great. No probelms, took it back to the house and parked for a week uncovered (was thinking i may take out anytime). It rained quiet a bit during the week so each day was, maybe tomorrow isn't raining.

I took it back out yesterday and it started at the ramp ok, as I was about to pull away it died. would not start back up this time.

i trailered it to the house, removed the fuel filter and drained it into a canister and the gas doesn't look good. It looks like it is mixed with a bunch of water and there are some small dirt particles in the filter.

I am not sure what you guys think the next step should be. Do you guys have experience with why the gas tank may have issues and allow water to come in? my deck is very solid, no soft sports, before i parked the boat for the year, it was running flawlessly and was parked covered.

could it be the gas line instead of the gas tank itself? How can I focus on what the problem may be and find out what the issue is? is it common for these gas tanks to do that? - Assuming that me thinking that the gas tank is the problem is true

[Capt. Bob]

What model year is this hull?

Never mind, it's an 87 so yes there is a very good chance your tank needs replacing.

still, it could also be bad fuel. Did you use ethanol fuel and if so, did you treat it?

[actualcivil]

The mechanic who did the work for me said he treated the gas and reused it. It may be a good idea to just dump all the gas and start fresh?

i always used Ethanol Free gas so ethanol was not put in it in the last 4 years.

any suggestions/ advice on how to dry out the tank ?

[Capt. Bob]

Well now you have another possible problem but I'm still guessing the tank itself is compromised. I would make an attempt to visually inspect the tank exterior and the "coffin" it is mounted in to get a feel for how much corrosion you may be dealing with here.

Non-ethanol fuel sitting in your system for a long time tends to evaporated and leave a varnish that may have broken up when "treating" the fuel and has re-migrated into your fuel delivery system.

One method is to run your motor on an external fuel tank to isolate the system.

[actualcivil]

Hi Capt. Bob,

I removed the deck plates (2) that can help me access the coffin. The one under the center console where the gas tank connections are and the one for the sending unit.

With the very little i can see (its extremely tight). I see a lot of gunk on the tank surface but upon removing (scraping lightly) the tank seems very solid (at least the areas I can access). I do not know for a fact since i did own the boat its whole life but the tank doesnt looks like its from 1987.

I think you are right, the next best option is to run on an external tank. replacing the tank seems like a rough one since it sits under the center console with all the controls and connections.

Do you have suggestions on whether i can permanently just run on an external tank?

[Capt. Bob]

OK then:
First, yes you can run on an external tank should you choose. Early Aquas came with an above deck tank often located in the center console. Others have run with the tank on deck in the stern. Either way, a tank of any size takes up valuable space on a 17' hull.

Second, replacing the tank is an undertaking but not impossible. You are fortunate that you have an actual tank access hatch. Later model Genmar hulls did not. Yes the center console covers a section of the hatch but it can be unscrewed and moved forward enough to allow hatch removal and tank R & R. A number of members have installed new tanks during the rebuild of a hull but others like myself (I've done two) have replaced them when they failed. First one I did was on my 84 - CCP and the situation was like yours with the console over the front portion of the access hatch. A 170 replacement is very doable.

Removing the hatch and seeing the tank will tell you several things. One is the manufacture date if the tag is readable (lower bottom right of tag).



Second, you'll see if there is water in the tank compartment aka the coffin. Most corrosion, commonly referred as "pin hole" occurs on the bottom and corners.

Something like this:


Note the black "bath tub ring" indicating the water level sitting in the coffin.



I would first try a small (6 gal.) external tank and see if the motor runs well. You may need to clean out the carbs again but maybe not.
If it runs well then you can make a decision on whether to have a tank on deck or install a new one. Capacity of the factory installed tank on that year hull was 27gals.



Good luck.