PARTIAL FLOOR REPLACEMENT

[osprey170]

I have a gas leak on my 170 and I suspect a rotted hose or cracked/pitted fitting on top of the tank.  It only leaks when it's more than 3/4 full and I can see oil/gas covering the top of the tank through inspection plate, also no water in fuel.

The aft portion of the decking that covers the tank is rotted and since I took up the console I noticed that the front portion is as well.  I would like to replace this portion of flooring but would like to do it with readily available materials.  Looks are not really important since only a small portion can be seen from the outside.  Most of this portion of floor is covered by console and flip back seat.  Of course I also want this to be a lasting repair.

I was thinking of getting a peice of plywood, cutting it to fit and covering it with resin then painting.  I've never worked with resin and/or fiberglass before.

Any ideas?

[Seadog]

A lot of the time repairs like these open up a huge can of worms: if your going to pull out the console to replace that section of the floor, you might find that the whole floor needs to be replace. You also might find other stuff that needs attention, like the stringers, and fuel tank.  Not a big deal. Take your time and do it right the first time through. We're here to help...

[jp aquasport]

$500 to do the tank hatch cover right. A glass pro will grind out the rotted wood,and epoxy
new in. Fuel tank is probably gone. New hoses and tank approx $425.

Stringers are glass...no wood.

[osprey170]

Thanks for the quick responses.  I have yet to get in and take a good look at the tank but I suspect a minor leak at top of tank since I only have gas coming out when almost full and no water going in.  Hopefully it's only a loose hose clamp or dry rotted gas lines.

On the floor... The peice I want to replace is the floor panel that covers the tank.  The way my boat is laid out this panel is mostly under the console and the flip back seat.  There is only about a 1'x2.5' section  that is exposed between the console and the seat.

I was thinking of removing this panel as one peice and using it as a template to cut a new panel out of plywood.  I was then thinking of encasing the plywood in resin and then painting it with deck paint.  I know this wouldn't be the prettiest thing but again most of this section of floor would be covered up.  I was planning on getting a pad to stand on anyway which will take care of the exposed area

My main concern is whether this would be a strong enough floor that would hold up for enough years to make it worth the trouble?  Again I know nothing about working with resin and/or fiberglass so I don't know if this is even a realistic type repair.

[Miguel]

I have the exact same boat and had the exact same problem.  
In my case, fuel was leaking from both the fuel intake and air vent fittings, where they are welded to the top of the tank.  Have you heard of JB WELD?  I used this product to cold weld the cracks almost three years ago, and have had no leaks since.  I have to confess that I was scared at first, but the results have been positive.
The part of the deck over the tank is completelly removable if you remove the console and flip seat.  I´m not sure if you could slide it out if you just remove one of them, say the console which has a lot of screws going in there.
It is basically a large fiberglass board (not sure if it contains wood).  As it has the original nonslip I wouldn't want to replace it with anything else.  I guess that with a lot of labor you could remove the wood and keep the outer skin, sort of like they do when rebuilding transoms. That way, you could encapsulate a new piece of plywood/other in there, while keeping the nonslip surface and matching color with the rest of the deck.
Just my $0.02 worth......

[osprey170]

Thanks Miguel,

Glad I'm not the only one!   There are two fittings on my tank, a 90 degree elbow for the fuel fill and another fitting for the vent.  I can't see the vent fitting since I haven't removed floor panel but I think it's leaking there.  The fuel fill had part of the floor resting on it and caused quite a bit of pitting.  My guess is this was caused by wet wood laying on the aluminum for extended periods of time.  From what I can see the vent fitting, assuming it's at least half as tall as the fuel fill fitting, is probably resting on wet wood as well and probably also pitted.  Hopefully I can find the leak from up top.

The non-skid is nice but not worth saving in my case - the floor was soft aft of the console and I reinforced it from underneath with some treated wood.  The non-skid surface is all cracked and broken.  The only part exposed is the small section where I normally stand when driving.  I had intended to put a pad to stand on here anyway so the non-skid is a non-issue.

So where exactly did you find the crack on your tank?  I too had thought of JB welding whatever leaks I found.  I've fixed cracked lower units with that stuff - it's amazing!

[Miguel]

osprey170:
I found the crack right at the neck of the fuel fill 90 degree elbow, where it intersects the roof of the tank.  The smaller elbow for the vent had a couple of full depth corrosion pits, but was not cracked.
The large crack formed when I unintentionaly jumped over a large tugboat wake.  Those things are mean!!!!!
The gas tank was full to the brim and I started smelling gas.  Sure enough, the bilge started filling with fuel..... Not good!!!!
As you mentioned, the floor rests on top of the elbow, which is a large part of the problem.  I solved that by leaving a large hole in the deck on top of the tank hoses.  No more floor pressure on the elbows.......
As I always say to other 170 owners: Please post pics of your boat!!!
Good luck with that tank!!!

[osprey170]

I'll try and post pictures soon.  My boat is not pretty but solid and a good overall fishing boat - and it's paid for!

I finally lifted the floor panel to check the tank out.  I found everything looked good and couldn't find the source of the leak.  My best guess is that it's leaking where the fuel fill hose meets the tank.  The fuel fill hose has seen better days and it appeared that it might not have been sealed tight.  There were two SS clamps and when I put things back I tightened them up as much as possible.  The fuel hose itself is very hard.  I know I need to replace this hose but it looks like it will be next to impossible with the way it's routed.  I may try and replace this hose this winter - it will take a lot of brut force and a lot of cussing to get it replaced but oh well...

[Miguel]

At first I couldn´t find my leaks either and the hoses became my main suspect.  When the elbow cracked, the deck was applying pressure on it, but because of the removal of the deck panel, the crack re-closed to a point where you could barely see it.
I don´t know if this is the correct way to do it, but I finaly found the leak by having someone blow some air on the fuel fill while I stuck my ear close to the tank surface.  Don´t blow very hard or with compressed air, as you may do more damage than good.

[osprey170]

I'm going to try and replace the fuel hose and then coat all welded seams on the fittings that I can see with JB.

I'll hold off on replacing the floor until the offseason.  I'll re-inspect for any leaks then.  In meantime I'm going to get back to fishing and avoid filling up my tank!

Anybody have any tips on an easy way to replace the fuel hose on a 170?  Looks like it was installed before boat was put together without much thought of ever having to replace it.  Couldn't I relocate the fuel fill to the console where it would be much easier access?

[Radioshop]

More than likely there's a notch on the top of the stringer to allow movement of the hose.  If it were me, I'd remove the filler hose from the tank elbow, then snake a rope down the filler hose.  Tie off both ends so the rope doesn't magically end up in the bilge.  Then tug old hose out.  Use the rope to pull in the new hose.  Take some cardboard, tape it to the end of the hose to make a needle point.  The needle point will help in getting the hose through.  Really, you're only making one 90 degree turn at the deck.  Also, might be good to use some electrical cable lube or, detergent to help slide things along.  The nice thing is the rope is going to keep you on path and, due to the rigidity of the hose, you can push and, pull.  This might be a good time to do the ventline.  Yes, you could re-locate the filler to the console, but in boat fuel fills are generally frowned upon.

[Miguel]

I agree with Radioshop.  I would not like to have the fuel fill in the boat.  May cause all sorts of problems....
I replaced my fuel line by doing a procedure similar to what he explained.  I used a plumbers tape, inserted thru the old hose.  In retrospect, a rope would have been much better.  The new hose should be a lot more flexible than the one you have in there, so it is not very difficult to pull the new one in.  Don't buy it to exact size.  Leave a foot or two for play.  Those will be cut at the end.
Just remember:
It is wise to double clamp your connections and don't forget to reinstall the grounds if you disconnect them.

[osprey170]

Thanks for the tips Radioshop and Miguel - I'll use the rope and maintain the stock setup - I'll also do the vent line while I'm in there.  The vent line actually looks like it may be harder to reach than the fill hose.  I bet that bit of elbow grease and a bunch of cussing will get these hoses swapped out.

Thanks again!

[pbailey]

I just did this to a 1975 19'6".  I thought the rope was the way to go since this is how I have replaced all sorts of things in boats before.  In this case the hoses are routed from the front of the tank and are routed over a notch in the main stringer and up to the fill fitting on a slight angle toward the bow.  Gaining access to the fill fitting at the underside of the gunwale was near impossible.  

I had to cut down the top, about 1 1/2-inches of the small channel that the vent and fill lines are routed in as they turn vertical to allow removal of the clamps from the fittings and hoses.  

When pulling the lines through, the rope got wedged between the outer and inner hull.  I had to remove the rope and start over.  I found that the fill hose is stiff enough to route on it's own so I taped the vent line to it.  The hard part is getting that fill line to make the turn upward.  I used a long crowbar and  stuck down through the fill hole (with fitting removed) and was able to coax the hose into making the turn.  You will need a flashlight also.

Definetly double clamp and make sure the grounds are in place.  I put all new grounding since I was in there anyway.

By the way, I could smell fuel too, but when taking everything apart and repacing the lines I couldn't point to any one thing and say that was the source.  The lines were old and in some places cracked and in others they seemed almost gel like.

No more fumes after hose replacement.

Just thought I would pass along my experience.  Hope it helps.

Safety note: do not use any electric power tools in or around the bilge with gas fumes present.  Air tools yes, electric no.

pbailey

[osprey170]

Thanks PBailey,  I got the hose out yesterday - man was it a PITA!  I thought it was never going to come out but I got it.  I disconnected the external fuel fill fitting from the hose and removed the fill fitting from exterior of boat.  Then removed the hose from the fuel tank and ran a rope through inside of hose.  I tugged the hose from the fuel tank side.  The hose was wedged between the outer hull and the inside of the floor.  I stuck a broom stick through the fuel fill opening and pushed on the hose until I got it unwedged.  I couldn't get it completely free - I couldn't really see what was holding it up underneath but I'm guessing it was one of the stringers.  Any way finally got it out - I hope the new one is easier to install.  

I was thinking of buying the new hose a little long say a foot longer and going further up towards the bow as opposed to the direct route the old one took.  This would avoid the narrow area between the hull and the deck.  I couldn't see how it would hurt anything.

I'll try and take pictures and post progress.

Thanks again for all the tips.