Marine carburetor; different from a car?

I have a stock engine 454 from a car, put in my Boat, and many people told me that i have to change the carburetor and the camshaft, because its different and it does not work well on the Boat..IS IT TRUE? do I have to Change it??? and what other parts??? What I can do?

Thanks in advance for any comments
Erick

Re: Marine carburetor; different from a car?

Well its not going to last long.

I'm no expert but I would think that the cam would not be high on the list.

The starter, alt, and carb are must be marine items for sfety reasons.

Some people have bent the tubes on some carbs so that the vent excess fuel back into the carb and not int the engine compartment of your boat, but even then Im sure if you look it up there are differences in the jets, meetering rods, and springs in your auto carb and a marine carb.

What kind of carb do you have on there?


All of the lectronics have to be marine versions so they dont spark and explode.

All maine starters, alts, and dists are sealed or some other crap that makes them safe.

Re: Marine carburetor; different from a car?

On most marine carbs the set up is changed so any excess fuel is dumped into the carb to choke it out and avoid it getting into the bilge.

Someone please correct me if I am wrong.

Re: Marine carburetor; different from a car?

Thanks my friend..the carburator is a quadrajet 4 barrel

Re: Marine carburetor; different from a car?

There are other differences. It may run good set as an auto carb but it will run its best as a marine carb.


I know on an edelbrock the secondary air butterflies have a lighter counter weight because there is less vacuum on a marine applicatioin sometimes.

And the jets, and meetering rods are a step richer on the marine version.

Re: Marine carburetor; different from a car?

The cam will work sometimes with a light weight boat and a big engine. It will not be perfect but might work you will need to try it. If you put all of this in a 3 or 4 thousand lb boat you will not be happy untill you change over everything to marine use. you really need to match up the cam with the advance in the dist and the jets in the carb. gaskets and core plugs may be a problem and like the other poster says you must use a marine starter alt, flame arrester and fuel pump. I may have left out some stuff. The jets will need to be the correct size or you engine will be toast in short order. water pump will have a short life.

oops was typing too slow again. forget all the duplication

Re: Marine carburetor; different from a car?

I believe on the Quadrajet there are the J's(don't know what to refer to them as) at the top and instead of facing in towards the throat of the carb(like on a marine) they face outward. I also believe it is against coast guard regulations because any excess fuel must be dumped back into the carbs to flood out the engine and not make huge explosions.

Def don't use a automotive alternator or starter ever due to the lack of spark suppression. That is a good way to blow you and everyone on your boat to bits.

Re: Marine carburetor; different from a car?

On an Edelbrock if you look at the carb with no air filter (auto) on you can see two little tubes next to the primaries sticking up through the top of the carb.

The marine one doesn't have these tubes sticking out. Some people bend them in somehow. But even after that the jets and metering rods are different and I think the accel pump.

Re: Marine carburetor; different from a car?

There are signficant differences between marine engines and auto engines. Read this, Marine Engine 101 http://newboatbuilders.com/pages/fuel-2.html. Marine engines are for the most part modified auto engines but it isn't cheap to do. Actually the 454 is commonly used as a marine engine. But if you try to run it without the mods it will be nothing but trouble, and you won't be happy with its performance. Some of the mods are for safety, some are there because the duty cycle (the load) on a marine engine is much different than an auotmotive engine.

Re: Marine carburetor; different from a car?

Short answer is that the cam is the least of your worries. All of the fuel system (fuel pump, carb, even the line materials and flaring, etc.) should be Coast Guard approved because the marine parts provide greater fuel and fuel vapor recovery or better durability. Almost all of the electrics (alternator, starter, distributor, etc.)should be Coast Guard approved because the marine variants provide greater spark protection, durability, and corrosion protection.

Anything that the raw water cooling gets in to should be marine grade because they will contain parts that have better corrosion properties. By that I mean things like the water pump. The marine water pump will have improved seals and most importantly a bronze impeller instead of the cheap pot metal impeller on the automotive pump. Freeze plugs should also be bronze. Head gaskets should be Stainless Steel, and if I also remember correctly, the intake manifold gaskets are improved materials too.

I don't even want to mention what would happen if you should be inspected by the Coast Guard (I have been once), and I won't mention your insurance either because you won't have any.

So yes, you CAN run an automotive engine in a boat, but SHOULD you? No. If you go ahead anyway, expect to have problems or a shortened engine life.

Wayne

Re: Marine carburetor; different from a car?

by its design the Q-jet works with USCG regulations.
may not be jetted properly for marine use but the design is the same for both auto and marine. you need a flame arrester on it.
the automotive dist may or may not be vented depending on which one your using.