5.0, 305 merc program

JFDee

Just bought a 2001 242 rinker with a 5.0..305 merc with a alpha 1 out drive.  Ran great at sea trial but smelt a little gas in the engine compartment.  Brought it home, washed the hull with dish soap and was bone dry.  Filled tank with gas, went for a run and boat Boggs down, sputters.  Boat runs and starts great, only Boggs down when giving her.bilge pumps out gas and a milky white substance.  Does anyone have a suggestion where to start as I'm new to boating and already want to sell. 

skennelly

Milky white substance sounds like oil being mixed with water.  If the bilge pump is kicking on because of this you have a pretty serious leak.

Fuel in the bilge?  #1 dont run the boat if you have fuel in the bilge... serious explosion Hazzard.

Check all fuel hoses for leaks...and also oil lines / pan for leaks.

LaRea

Absolutely DO NOT start the engine if you smell gas in the engine room. 

You're new to boating, so maybe you don't know the danger.  Gas fumes are heavier than air.  Unlike with a car, fumes will accumulate in the bilge, and a spark can create a major explosion.  Even a small gas leak can be deadly because the explosion can throw people off the boat.  

Park the boat until you find and fix the fuel leak.  

JFDee

I emptied the bilge and disposed of the liquids properly.  Washed the hull out with Dawn dish soap.   the smell is gone.  Local marine guys told me to turn the key to pressurize the system.  No leaks around the hoses and no leaks around the oil pan.  The white "milky substance was from the original soap I used to clean the hull.  

skennelly

Perhaps you have a leak in the fuel tank and underway it sloshes around and is able to escape to the bilge

JFDee

I'll start there by pressurizing the tank and see if it holds.

Willhound

@JFDee it's good that you don't see any leaks but did you ever determine where the smell was coming from? Is that engine EFI or carb? If carb and it was running rough and bogging you could have bad spark plugs or wires and unburnt gas is spitting back out the carb?

JFDee

EFI.  I'm going to have the mechanic go thru it.

JFDee

I believe I found the leak.  When the boat was in the driveway or in the water, there was no smell.  When taking off the bow goes to and the tank is at an angle.  the fuel sending unit is at the stern part of the tank and I noticed that one of the screws are sitting up and I can stick a very small screwdriver in past the gasket about .500 inches.I hope that is where the leak is coming from.  Any thoughts?

aero3113

Sounds like that could be it. You can remove all the screws pull the sender out, clean the gasket and mating surface and reinstall. Or just tighten the screw and hope all is good.

212rowboat

that is likely your issue.  use a new gasket, and in this application cork is better than rubber.  

also take note the fuel line vent likely vents into the bilge... which i think is kinda crazy but i don't have a better solution either.... some folks overfill the tank and it comes right up the fill tube and right down the vent line.  keep that in mind while filling.  

JFDee

thanks for the advice.

aero3113

Did you get around to pressurizing the tank? If it’s leaking there it will be obvious.

Ian

212rowboat said:

also take note the fuel line vent likely vents into the bilge... which i think is kinda crazy but i don't have a better solution either.... 

Interesting, didn’t know this an wondered where the vent was as unlike my prior Bayliner there isn’t one near the fill up. I’ll have to go looking - and explains the gas smell below for a little while after a fill up.

aero3113

It should vent out the fuel fill, follow the vent line and it goes up to the fill neck, the cap is vented.

raybo3

I doesn't vent into the bilge. Like aero3113 says it vents through the gas cap.

212rowboat

so y'all think that tiny hole in the cap allows for the draining (better said disallows vapor locking) of fuel? 

yeah, it runs adjacent/parallel to the fill tube.  bilge is not the term i should have used though... engine compartment is.  the tube open adjacent the cap under the glass and protected from intrusion of debris.  it is on mine, anyway.  i can't say that i've purposely removed a fill tube on any other inboard, though.   

raybo3

212 there is no way it vents in the engine compartment. NO WAY!!!

aero3113

212rowboat said:

so y'all think that tiny hole in the cap allows for the draining (better said disallows vapor locking) of fuel? 

yeah, it runs adjacent/parallel to the fill tube.  bilge is not the term i should have used though... engine compartment is.  the tube open adjacent the cap under the glass and protected from intrusion of debris.  it is on mine, anyway.  i can't say that i've purposely removed a fill tube on any other inboard, though.   

Either your vent line broke off or slipped off the barb on the fill neck. Your fill neck should look like the one in the link below.

https://perko.com/catalog/fuel_system_components/158/sealed_ratcheting_cap_fills_with_pressure_relief_for_1-1_2%22_hose_-_angled_neck/

GMSLITHO

How would it vent back inside the boat kaboom 

JFDee

Mechanic hasn't been able to work on it yet to pressurize it to make sure that is the issue.  I'll keep you posted.

JFDee

I fixed the gasket and 3 screws were loose.  Comparing the old gasket to the new gasket was much different.  The old gasket may have been deteriorating over the years. cleaned the surface area and positioned the new gasket(holes only lined up one way),  drained all the fluid from the bottom of the boat, washed with dawn and smell is gone.
 

JFDee

As for venting, and learn so much about boats, I see two lines going to my fill cap, so I assume one is fill ,Large 1.5"DIA and the 5/8" DIA is the vent line that vents out the gas fill area.  Just my observation though, I could be wrong.

Willhound

@JFDee it sounds like you found your issue, nice work. Keep an eye on it (and a nose too!). You are correct on the fill and vent line and contrary to what may have been posted, the vent exits at the fill cap not in the bilge. If anyone has that vent line loose in their bilge it's because it's pulled off somehow.
As always, run your blower minimum 3 to 5 min's before starting up. And it doesn't hurt to give the exit vent a sniff too before starting up.
Many of us will also open the hatch when starting for the first time of the day. A good opportunity to check engine oil dipstick and do a visual check on other fluid levels like drive and trim fluid and just the general state of things.

JFDee

Willhound, thanks for the advice.   It's been quite the learning experience so far.

LaRea

As I've said here many times ... I always sniff the blower exhaust before starting the engines.  Every time, without fail.  Sounds weird, but you'll understand the logic if you spend a few minutes on youtube watching videos of boat explosions.  Here's one for you ... imagine if you were standing right above the engines:

https://www.youtube.com/watch?v=lpFjkL1YvBI

Get to know what "normal" smells like for your engine room.  If the odor is anything other than normal, investigate before starting up.  

212rowboat

So yall scared me and I went to look. 

There is (was) a third hose zip tied to the fuel inlet/vent that followed it almost to the cap and then bent toward the helm in the routing passage between the top and lower shell/hull.  It ended about a foot after the bend.  It went atop the tank toward the bow, but wasn't (or at least wasnt well) connected to anything.  I have always left it alone believing it a vent. 

I'm thinking perhaps the prior owner used it to route wiring possibly?  There was, when I bought the boat, a cooler under the aft seat that was drilled and a couple wires coming through side near top.  I saw it for what it was: a makeshift bait or live well missing its pump/aerator (sp?).  I pulled the wires straight out of it, and there must have been 15~20' of it... I bet you all a dollar it went through that hose at one point and to a rocker switch at the helm... 

So I'm relieved. Ive never really thought about it until now and y'all talking about venting... 

Willhound

Right on @rowboat212 that's what it's all about.

JFDee

LaRea, Funny you say sniff the blower, That's what I did the first time I turned it on.  Like I said before, I smelt gas from the blower for minutes after I turned it on, since I fixed the sending unit gasket and dryvack 90% of the water out of the hull, I turn the blower on and for about 3 sec get a faint smell of fume the get a fiberglass boat hull smell.  Is this what you are referring to?  Is that normal?

Willhound

Sounds about right.

LaRea

Every boat's engine room might smell a bit different.  It's a combination of fiberglass outgassing, bilge water, and residue from every fluid that has ever leaked in there.  Once you understand the normal odor for your boat, you're just looking for anything different ... fuel, anti-freeze, oil or anything that smells like burning or overheating.