Lost all my oil...again

[nola mike]

Went about 25 miles today. Last mile or so, I noticed that the oil pressure was hovering/bouncing a bit at 50 psi (usually it's 60 at the speed I was going). I was keeping an eye on it, and then it dropped to zero while doing 3k-ish rpm. I immediately (?) shut down. Unlike last time, the carb didn't have time to run dry after the fuel pump shut down. Luckily, I was maybe 1/4 mile from the launch, and got my workout by swimming it in. When I investigated, I saw that the fitting connecting the OP sender/fuel pump switch had cracked right at the block. This is the exact same thing that happened to me right after installing the engine last month . The fitting is an off the shelf plumbing nipple from lowe's. I thought last time that I might have knocked it, but this time definitely not. Must be from the vibration. So, assuming I didn't ruin the block, what am I doing wrong here? Is it that it's a brass fitting? Should I be using something different? Do I need less weight on the end of it? This can only happen so many times before my luck runs out.

 

[nola mike]

[No message]

 

[Scott06]

That’s a lot of weight cantilevered off the block. Might try getting a steel Sch 40 or sch80 nipple which is thicker wall and see if you can ditch the 45 and first nipple. McMaster Carr has all this online can deliver if you don’t have a plumbing supply house local.

I think u can also tap into the pressure circuit by the distributor as well. The 4.3 that originally came with my boat had the low oil pressure switch there.

if you have tight clearances get a braided flex line mount the heavy t with senders on the boat or seat frame connect flex line to block kind of like a remote oil filter.

 

[nola mike]

This is mounted by the distributor. Is there another location that I can tap into? Not sure that I can do any other setup other than what I have. How are others mounting theirs?

 

[Rick Stephens]

That's where mine is mounted. I used a steel 2 inch nipple, and a machined Tee.

 

[alldodge]

The fittings are being over torqued. Brass fittings just need a good snug. I'm running close to 90 psi and your motor is probably around 60 psi

 

[kenny nunez]

2Xs on ScottO6. I like to also mount the senders with a stainless braided line. Mercruiser hydraulic lines work perfect and also provide a ground.

 

[nola mike]

Didn't gorilla tighten the fittings. I tightened by using the last link in the chain, so the loosest fitting was the one that turns, if that makes sense. But the thought of over torquing that small fitting definitely crossed my mind. I think a steel fitting would be stronger, Rick Stephens do you have a pic of your installed setup? I'm battling the distributor and throttle plate back there. Don't know where to get flex lines, and don't want to run 10'of line. I think it's cleaner to have everything at the engine

 

[Scott06]

Mine are mounted just above the oil filter The is a single switch for oil pressure alarm by the distributor, and the fuel pump Oil pressure switch And oil pressure sender are just above the oil filter.

 

[Scott Danforth]

the fittings from Lowes are chinesium brass

go to Napa, they carry weatherhead (Made in the USA)

 

[Baylinerchuck]

McMaster-Carr also sells stainless NPT fittings. Would be a nice upgrade over the brass. I have had the brass fittings from Lowe’s crack, mainly the 1/8” NPT and IPS fittings.

 

[todhunter]

I'm new to boats, but well versed in cars. Big weights cantilevered on rigid fittings on the engine will eventually crack due to vibrations. I second the suggestions for running a flexible line and remote mounting the sensor. For cars, I tell people to find a local hydraulic hose shop and they can make you up the hose with the ends and length you desire.

 

[chs marine service]

as Scot said, move the o/p sensor and fuel pump switch to the oil filter location, you'll need a 1/4" to 1/8 reducer, a 1/8" tee and close nipple.
the set up you have is way to long and heavy.

 

[nola mike]

Ok, I was able to eliminate the 45' and use original nipple, and then a tee on top. That should eliminate a lot of the leverage on the fitting. Also put the switch directly above, so again, less weight against the straight section. Straight section is also now 1.5" v. 2". Lastly, that brass nipple was crap, as @Scott Danforth said. Take a look at the wall thickness between the 2 fittings. Between all this, I feel much better about the setup. However, when I started it up it ran like absolute crap. Unable to idle without dying, sounds like it's missing at all speeds. Oil pressure was good, no funny noises. I lost about 2 qt oil total. Carb looked like it was flooding down 1 barrel, but I'm not sure if that's just because I needed to crack the throttle to keep it running. Here's what I did:

1. Took top off carb, verified float settings. No crap in there, needle valves/seats looked good. Sealed well when upside down and I tried to blow into the intake.
2. Checked compression (first time since I first got it when it was straight from the junk yard). Almost dead on 150 on all 6, and pressure jumped up quickly.
3. Checked fuel filter. Looked good. I was hoping to find some water.
4. Tried to check spark and timing. It was missing a bit with the timing light, but the idle was so low and rough that I don't know what to make of that. At 800rpm (again, throttle was cracked), timing was around 10' btdc. Going to try again later.
5. Tried readjusting idle screws, didn't seem to make much difference.

Again, everything was working well last weekend before losing the oil. Anything catastrophic/engine related that I'd be missing at this point?

 

[nola mike]

Well, verified that the carb was flooding. It fixed itself though, and then everything magically started working, idle smoothed out, vacuum increased, missing stopped. Must have had more gas going in there than I appreciated. Not sure why it keeps intermittently flooding though, and the timing was very odd.

 

[louc]

All it takes is a tiny bit of crud getting past the filter and jamming the needle valve open....or if it starts to happen often the needle valve may be damaged and not sealing

 

[nola mike]

All it takes is a tiny bit of crud getting past the filter and jamming the needle valve open....or if it starts to happen often the needle valve may be damaged and not sealing

Yeah, except "Took top off carb, verified float settings. No crap in there, needle valves/seats looked good. Sealed well when upside down and I tried to blow into the intake."

Like I said, strange to do this at the exact moment I dump my oil. Oh well, I'll take it. Also I found it a bit strange that the rough running persisted at 2k rpm (but on muffs). I wonder if something got in there on my trip home, but it didn't affect it under load at 35 mph.