Issues with Fuel Vapor, Carb repair, Electrical drain

[Assassin3F]

This one is a real trifecta...its actually worse than that since what I have found so far scares the crap out of me about what I am going to find next...there is a real downside to understanding potential problems it seems...

I recently bought a 2000 Wellcraft 175 SS; The Power Package is a Volvo Penta SX 3.0L (engine info 3.0GSPEFS; built by GM in 1999) I grew up around boats but am tackling a number of issues in the engine compartment and I am looking for advice. The engine runs but I am told it is a very hard cold starter but good when it warms up (more on that below.) When I looked it over there were a number of items that I missed prior to purchase or did not think to check so I am now going over the engine with a fine tooth comb. I know it runs but I don't want it to run until I am sure it won't kill the engine or outdrive.

Issue #1: I have a battery drain...a big one enough to bleed it dead in approximately 3 days. I think it is located in the bilge pump (which is the only switched device which does not work) so I am going to start by cutting that circuit out and putting in a new device. Battery is recharged but disconnected at the positive terminal at the moment.

Issue #2: An ungodly amount of fuel vapor around the engine and yes this bothers the crap out of me. I have removed the engine cover and bulkhead for access purposes (I am 6'3" 250, squeezing behind or under an engine is a little difficult) but I keep the boat covered when I am not working in it and the cover does go over the fuel cap but the boat is stored and worked on out doors. There is no fuel or water in the bilge or under deck spaces but the vapor build up is intense, to the point that I bring out a box fan when I uncover it and blow fresh air all over the vehicle prior to getting in then leave the box fan blowing into the engine and bilge spaces to KEEP them clear. I am very concerned and I am looking for advice on dealing with this issue. There is no fuel in the bilge or seeping out into the under deck spaces. It has rained a couple of time and small amounts of water have gotten in the boat (less than a 1/4 cup) with no sheen of fuel/oil smell/texture) The hoses appear to be newish or at least in good condition, but I am going to inspect the penetration points at the tank and hull interface this evening.

Issue #3 in conjunction with #2 above. The carburator choke (thermostat housing I believe) is broken. As in a chunk of plastic is missing from the housing and you can see inside. I believe this is supposed to be able to pull a vaccum and it is clearly a gigantic vaccum leak. This is something that actually gives me a lot of hope with respect to the fuel issue. I am going to buy a new base gasket for the Carb and a new choke cover this evening from an auto parts store (I know you are supposed to use marine parts but I think the choke cap has to be in a vaccum to operate correctly so it should be the same regardless of carb??). I suspect the float needs to be replaced as well.

What I think is happening is the boat is outdoors in the sun all day and the fuel in the tank is heating up enough to lead to a slow drip in the carb. I think the float is filled with fuel and not shutting off the needle valve in the carb and the hole in the choke housing is letting the fuel evaporate all day. What I am hoping is that I can swap out the float without doing a full strip and rebuild.



I am going to inspect the impeller, and outdrive before I try to put it into the water (also the bellows etc.) and I am contemplating pulling off the drive before making any attempt to flat the boat (by the way this site gave me a great idea for a cheap way of getting the drive out and supported) but the following are my questions concerning the above issues.

1. On the battery drain if the bilge isn't the problem what is the best tool for tracing the system? I have a multi-meter and have been following a procedure where I disconnect the positive terminal and bridge the gap with the meter then disconnect devices until the voltage potential drops to zero. But no dice. Now that I have obtained a wiring diagram (courtesy of this site). I realize that if the short is in the grounds (any of the grounds) this will not find it since they are all spliced together into a type of circuit bus. Is there a tester I can use? I saw a couple at harbor freight that were cheap and 'might' help me but I am unsure of what device to use or how to configure the system so I know I am doing the right procedure.

2. Can I pull the fuel sump off the Carb without doing a full rebuild? I know you are supposed to do a full rebuild but I don't have time at the moment...what I am wondering is if I can just pull the sump off right now and replace the float and choke housing put a couple of new gaskets on and see if that fixes the fuel problem.

3. I read out here that you can run your hand or a damp rag on the fuel lines and if you smell gas you know what you need to do with the lines. If that isn't the problem how do you tackle the rest of the fuel tank? Some of the tank penetrations are visible in the engine compartment or through an access hatch but I think there is one that is beneath the deck and I cant get at it without tearing up the floor.


Any advice or responses are appreciated in advance...I am certain I will have more issues as the 'inspection' goes on.

 

[Fishermark]

On the battery drain - it may just be a bad battery. You should take it somewhere and have it load tested.

On the fuel vapor smell - I would suspect the hoses, not the carb.

On the choke cover - that is probably the electric choke element. Do you have a mechanical or electric choke? Either way, I doubt that has anything to do with the fuel smell.

 

[jerryjerry05]

The radio or depth finder if left plugged in can draw the battery down.
​I'd get a load tester($25 Harbor Freight) and a Hygrometer for battery maintenance.

Hot battery, everything off.
Unhook the ground lead and put in a test light between the N post and the end of the cable.
Then if the light comes on there is a drain somewhere???
Start at the fuse panel and start pulling them one at a time until the light goes out.
That will be the one draining the system.

Sometimes the depth finder is just butt connected into a hot wire.
So you might have to unplug it at the back of the unit.

The fuel could be the float in the carb?
Check the oil for fuel contamination.
A few drops a day can cost you an engine??
The hoses might be suffering from Ethanol.
It delaminates and can cause hoses to swell; and rupture.

Check the hoses, the vent line too for a bad connection.
Or worn spots that the fumes can leak through.

Unhook the vent and try blowing through the hose.
See if you can hear any leaks or if it holds pressure.
The cap should be air tight.
Don't use compressed air to a tank.
Can cause an explosion.

 

[Assassin3F]

Thanks for the safety tip on the compressed air Jerry. The Leak was at the Fuel Sending Unit I popped off the access cover and it was misting fuel into the tank area when the boat heated up in the sun I cleaned the heck out of the area as best I could and tightened down the sending unit good and solid. The gasket expanded when I did this so I think it was just loose I also bought a replacement gasket kit but I don't think I need it right now since the leak stopped. I also vented the compartment with a box fan for three days alternating from drawing air through the compartment with the fan and blowing air into the compartment. At this point I think I got it as cleaned out as possible.

The electric issue turned out to be caused by a mis-routed bilge line. The previous owner decided to put in a Siphon loop high by the exit to route the pump between the engine mounts. Unfortunately he inadvertently air-locked the pump and burned it out leading to the short across the motor. I re-routed the flow line replaced the pump and removed the 10 amp fuse he installed (apparently in ignorance) and replaced it with the 5 amp fuse for the new pump. Battery holds charge and the voltage leak is gone at the battery.

Quick question: What is the best way to seal unnecessary screw holes. The old pump had three the new pump has 2. I currently have a screw in the old hole to keep it just as water proof as before but I am wondering if I should put some quickie epoxy in the hole instead.

I got a replacement choke cap ordered and I am going to replace it when it comes in.

I put it into the water over the weekend and did a leak test and run test. Everything looked good and we puttered around at about 1/2 throttle for 45 minutes while I adjusted the trailer and replaced one of the bunks. One thing I noticed is there seemed to be a lot of exhaust behind the out drive...more than I am used to seeing in my experience (bearing in mind most of my experience is out of date by 20 years).

I know this is a bone headed question (or at least it seems like one) but if the exhaust in the water at idle seems excessive does that indicate any other engine problem?

 

[jerryjerry05]

Since the choke isn't complete??
​Possible it's burning more fuel or burning at the wrong mix?
Does the carb have air screws?
Do a compression test?
Pull the oil cap while running and see if there is any blow back?

The screw holes: it's best to let them dry out first.
Then any waterproof silicone or 5200.
Put it on the screw threads and reinstall.
Even the screws holding the pump.

It should have a loop if the outlet is close to the water.
Or it can siphon water back in.

 

[Assassin3F]

I am going to check the bilge line next time it goes in the water I straightened the line cause the loop at the hull fitting was sagging below the outlet which was air locking the pump and causing burnout. the guy who owned it before me had some blown 5 amp fuses in a cup holder and a ten amp in the panel for a pump that required a 5 amp fuse for protection so I am assuming he didn't realize what the problem was at the pump. The exit is just under the swim deck so I will probably have to give it a hard look to make sure water isn't leeching in up the line or add a loop back in that is supported better.

 

[Assassin3F]

Another question that has come up is in regards to the drive. It is a VP SX-M Drive. Before I took it out for a run test I checked the lube level in the drive and it read full. Since I am replacing at least one and possibly two U-joint bearings I hired a guy to do the bearing replacement and he said the lower unit didn't have any lube coming out when he pulled the drive. I am wondering if it is possible if the guy before me filled the lube reservoir from the top that the dipstick in the unit would give me a false positive. I was under the impression that if the unit was down and had been left to settle over night that the lube level would be accurately reflected in the dipstick but now I am wondering if something squirrelly is going on. There are no obvious leaks, no fluid trail or tell tales on the drive so if it is leaking then I would assume it is the prop shaft seal. Is that a good assumption?

 

[bruceb58]

Your drive does not have a lube reservoir.

Did he pull the plug at the very bottom of the drive near the prop?

The drive should always be filled from the bottom until it comes out the oil level hole which is back behind your gear linkage. Does this guy work on Volvo drives?

Who filled the drive last?

 

[Assassin3F]

The previous owner had it filled last I just checked the level and condition of the oil by putting the drive down full waiting a day and pulling the dipstick. The lube looked brand new and the level was right at the proper level so I assumed (which is killing me right now) that the level was correct and the gear lube was golden.

What I was concerned about is if the previous owner had filled it from the dipstick could that give it a false positive? And of course leave me sitting here wondering if I just shot the lower unit.

When I was referring to the reservoir I was only refering to the cavity that you pump the lube up into. I was unsure if there were any shelves or cavities up top that would lead me to believe the drive unit was full just by checking the dipstick when all the lube was trapped in the upper unit do to a fill error.

My question was more related to either confirming that I did the right thing when checking the lube level or if I have to pull the vent screw and fill screw to confirm that there is lube in the drive in the future.

 

[bruceb58]

How long before you checked it was it filled by the previous person?

You checked it correctly.

Which drain screw did the repair guy remove to drain the drive?

 

[Assassin3F]

I don't have any info regarding the last fill date. I will discuss the fill plug and vent plug with the service guy that mentioned it to make sure he is aware of the need to take off the top cover to get at the vent screw.

And thanks for the confirmation it actually is putting my mind at ease that I didn't just accidently shred the drive due to outright stupidity.

 

[bruceb58]

It's not the top cover. It's the back cover that is held on with 3 screws. Make sure that whenever you change the gear lube, you replace the o-rings on the 2 plugs and the dipstick.

Here is where the vent is

 

[Assassin3F]

Just to be clear there is no other fill point for the VP SX drive lubricant? I don't want to make anymore bad assumptions.

 

[bruceb58]

You fill from the bottom hole which is down near the prop.