your problem is that without the drain tubes it's cause for an insurance company to void your policy and claim in the event of a fire that started in the carb. same thing goes for using air filters instead of USCG approved flame arrestors - of course, you're In Canada so I not know what your version of the USCG allows/disallows up in the great white north.

 

so yours does not have this tube?

 

The quadrajet that I was originally running had a fitting coming out the side of it right above the gas line entrance with a 1/4" rubber hose leaving it.The one i have now does not have this provision and it does not have that little metal tobe coming out the top as shown in your picture.

 

Why didn't you just buy mine? :wtf

 

Only paid $50 for this unfortunately now I think I know why.I am pulling my boat out this weekend for the season and looking at doing some overhauling over the winter and will get intouch if I need a real one in the spring.This carb does make the boat move alot faster than my old one and was advertised as a performance type carb.

 

Only paid $50 for this unfortunately now I think I know why.I am pulling my boat out this weekend for the season and looking at doing some overhauling over the winter and will get intouch if I need a real one in the spring.This carb does make the boat move alot faster than my old one and was advertised as a performance type carb.

Is the new one a Q jet?

 

just buy the tube and put it in.

 

The new one is indeed a q-jet.

 

My engines were stock 365hp mag engines with qjets. They didn't have that curved tube, just a mitered end on the vent tubes. They were stock mercruiser carbs when I bought the boat I'm pretty sure.

 

My engines were stock 365hp mag engines with qjets. They didn't have that curved tube, just a mitered end on the vent tubes. They were stock mercruiser carbs when I bought the boat I'm pretty sure.

Same here. All stock and No J tube.

 

My engines were stock 365hp mag engines with qjets. They didn't have that curved tube, just a mitered end on the vent tubes. They were stock mercruiser carbs when I bought the boat I'm pretty sure.

Me three... I have two and from all outward appearances they are automotive, but they are the factory Merc carbs. They even have the serial number tags from Mercruiser.

 

The non Marine will void the insurance in Canada

I seen a lot of guys trying to put Automotive carbs on.






http://www.marinetoys.ca
Marine Toys
Performance Accessories
Vancouver BC

 

Me three... I have two and from all outward appearances they are automotive, but they are the factory Merc carbs. They even have the serial number tags from Mercruiser.

Me Four.. same deal here on a stock 89' with twin big blocks...

 

Me Four.. same deal here on a stock 89' with twin big blocks...

Me five. Same thing on my stock 454 Crusaders.

 

Me three... I have two and from all outward appearances they are automotive, but they are the factory Merc carbs. They even have the serial number tags from Mercruiser.

I think the question begs a call to Merc Tech Support.

 

I am pulling it out for the season on the weekend and I will check out carb after that.It doesn't have any tags suggesting it is a merc carb but I will check it out further.

 

besides the "J" tube , marine carbs have a groove machined into the throttle shaft redirecting fuel into the throttle bore . If your boat burns down to the waterline , you might as well pull the drain plug in 600 fathoms of water and sink it :laugher: . Buddy of mine had his boat burned to the waterline back in the early 80's , but the engine block , Arneson drive and tranny stayed in tact . The insurance company was able to check if he had the proper marine equipment installed .

 

Me seven....89 stock Merc 365hp 454 mag HO.....same

 

A Marine carb has the throttle plates mounted on the BOTTOM of the throttle shaft.
That is a dead give-away if it is a true marine or "Modified" to look like a Marine.
The throttle-plates below the shaft makes the idle ports in the body of the carb below the shaft so they are less likely to leak out the shaft onto the manifold.

Also as stated above the throttle shaft bore is grooved to drain fuel inside the carb and not be able to make it out to the mainfold.

 

I could be wrong but isn't the tube in question for use with mechanical fuel pumps? My first boat had a tube that ran from the bottom of the mechanical fuel pump to the carb so that if the diaphragm in the pump failed the leaking gas would go to the carb and not the bilge. My 1983 Camaro just dumped the gas on the ground or into the oil pan when the diaphragm failed. My previous boat with electric fuel pumps and Mercarbs didn't have the fittings

 

Me seven....89 stock Merc 365hp 454 mag HO.....same

Why can,t you attach your own j tubes on the stubby ones You can make them and slide them over the originals with some liquid epoxy to hold them in place...Joe

 

Why is a boat more likely to have a carb fire over a car with the same carburator.

 

Why is a boat more likely to have a carb fire over a car with the same carburator.

I don't think it's because it's more likely, just that marine carb's are designed to be safer, because if there's a leak there's more of chance there will be an explosion..!! from the fumes that settle into the bilge, where a car is open under the engine..

If it goes in a boat, Marine carb's are the way to go. period.

 

When the debate of auto vs. marine carbs come up, I always think about the story my buddy told me about his mom getting blown 30 feet from the boat, while she was sitting on the sundeck when his dad started the engine. Just installed a "high performance" engine and used a regular, non-marine Holley. She was not hurt, but filled her bikini bottom with poo.

 

Why is a boat more likely to have a carb fire over a car with the same carburator.

My thought is that the fuel vapors are trapped in a boat hull and the simple act of the starter gear engaging into the ring gear can spark a blast. Fuel vapor is heavier than air so on a car most likely the vapors would be drafted away from an ignition source. Even the alternator brushes can cause an explosion if fuel vapors are present.


Keep the engine bay bilge on and no worries. Let vapors build up and after an explosion a person might not be able to worry about it