Griff

I believe Nickerson sells them

thirdchildhood

iTrader: (6)

Pretty sure the throttle shaft has seals on the ends.

dereknkathy

the only diff is if float sticks and floods out, the j-tube pours the gas into intake and shuts off motor instead of filling the bilge with gas. that being said, it is a pretty big diff.

FIXX

iTrader: (2)

ok how many have you seen burnt to the water line and the carb is still intact?? none!

gmhdfan

Thank you. Someone did post what the difference was once on here, but mostly J tubes (cheap to buy) and the shafts are different. Do a search someone stated the difference on here one time back. And the 420 motors had a angle spacer between the carb & intake. And how many people aren't running marine starters? Just saying...

tbanzer

I have seen one burnt to the water line. All aluminum was melted including the carb. The J tubes and throttle shafts would be able to be identified because they are made of steel and would be laying on top of the intake.

Budman II

iTrader: (1)

Not sure about the throttle shaft thing. Last year I was curious about that, so I did a test. I bolted a marine Holley to a loose intake and poured about 6 ounces of gas down the throat - this should simulate most flooding situations. Most of the gas went down the intake, but a little bit did seep out of the throttle shafts. Followed up with an automotive Holley, and got pretty much the same results. That being said, I read on Holley's site that the metering blocks are a little bit different for marine carbs due to the different running conditions and loads of marine applications.

picklenjim

Merc Manual states changes made to 850 DP being
Vac tube removed and 1/8" NPT plug installed
Power Valve primary metering block only
Primary metering block idle feed holes drilled to .040"
Vent holes in main body drilled to .316" for installing "J" tubes

I converted one of these and yes the "J" tubes are slightly larger than the stock street vent tubes.

If you plan on buying "J" tubes shop around on the net. I've seen them as cheap as $6.99 and as high as $35

sprink58

OK...with a starter you CAN blow your a$$ up!!! Gasoline fumes and a sparking starter don't mix...you might as well throw a lit match in the bilge. Besides all that...they won't last very long at all...automotive starters can't tolerate a marine environment and rust up quickly.

If you HAVE to use an automotive starter for Gods sake vent the bilge with an open hatch and blowers running!!

1989force

The marine carb will not let gas past the seals on the shafts, as well as dumping gas back into the intake in the case of a stuck float. Legality aside, it just isn't worth the risk to your family and friends to explode or burn over a couple hundred dollars. If something bad happens and you could have prevented it with something as simple as a approved carb, you will surely wish you had done so . I don't have the slightest idea how litigious Canada is, But you can be sure that if you are sued, and you don't have approved equipment, you are totally and thoroughly screwed, in both civil, and possibly criminal courts. If you do it right the first time, you won't regret it as you are doing it over the second time.