Ski Boat Forum
General Category => General American Skier Discussions => Topic started by: JBBBM on July 21, 2015, 11:39:17 AM
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How do you tell?
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take a pic with the spark arrestor off - then we could see even more of it - if the vent tubes go straight up - its automotive, if they are upside down J then could be marine, Holley 4160 (600cfm) was most commonly used on our engines, this one is a 4150 - you would have to research the list # to verify the cfm
so how does it run?.......... I see vacuum advance on the (non marine) HEI igntion - Marine uses either mechanical advance or electronic advance - vacuum advance doesn't work so well as boat engines are ALWAYS under load (except in neutral)
Dan T
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Just bought it 7/15/2015. My first boat. Had 508 hours when I bought it. Ran it for 7 hours on Saturday and it ran GREAT!
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First clue is the standard auto Dizzy like Dan pointed out. No marine engine that I know of ever used a vacuum advance dizzy. If the dizzy is automotive, I would bet my next paycheck the carb is too.
Second clue is the external adjustable, center hung float bowl on the carb. No Holley marine carb ever used one that I'm aware of. They're all side hung and internally adjusted.
I would highly suggest that you get the proper dizzy and carb on there to prevent the possibilities of a fire or explosion. Marine engines can certainly run with automotive components but carb, dizzy, starter and alternator are marine rated and USCG approved for that reason. Better to be safe than sorry.
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WOW! Fire more susceptible at higher speeds?
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Not necessarily.
It's all a matter of leaking fuel putting explosive gasses in the engine compartment. Then you have spark from the dizzy, the starter or the alternator that sets it off. That's when you get the fire. Whether that happens at startup, idle or WOT doesn't matter. You don't want it happen at all. Closed marine engine compartments have no place for raw fuel fumes to go except sit in the bilge waiting for a spark and the reason for a bilge blower that should be used before every engine startup.
Auto's don't have that problem. Raw fuel leaks dump on the ground harmlessly and evaporate away. Usually. But fires still can and will happen.
Marine carbs have sealed throttle shafts and "J" vent tubes to dump any excessive raw fuel down the throat of the carb and into the engine. It'll flood the engine but won't dump raw fuel into the bilge. Auto carbs don't.
In the event of a diaphram rupture, marine fuel pumps route raw fuel up a separate hose to the carb for the same reasons I just listed. Auto fuel pumps don't.
Marine starters and alternators are sealed for spark suppression. Auto units aren't.
Marine dizzy's are vented with screens that act as mini flame arrestors just like on your carb to prevent sparks. Auto units do not.
These are the reasons that Marine rated parts are considerably more expensive and the average guy...aka, cheap ass....has no idea why so they figure it's OK to just put automotive parts in it's place.
So your automotive substituted parts may work fine and probably run for years without an issue and nobody is the wiser. All in the name of saving some bucks. All it takes is one isolated freak accident to totally ruin your day, your life or someone else's life. So you have to ask yourself....How many dollars is it worth that would possibly prevent that one freak accident?