what makes a tbi from a truck different then a marine setup?

[lime4x4]

Just curious.I've worked on gm engines for the last 20 years.If u look at a tbi system on a truck the injectors are sealed and if there ever going to leak are going to leak into the intake. The dist has a vent hole in the bottom plate with a screen over it.They use 14 psi of fuel pressure. I just don't c what all the fuss is over people using a truck tbi setup on there boats. U can get an external marine fuel pump that is rated for 14 psi. U can have flexible stainless steele lines made up that are rated up to 1000 psi or more

 

[DJ]

Re: what makes a tbi from a truck different then a marine setup?

Whether they are the same or will work, is NOT the issue.

The issue is, if they don't carry a marine rating and something happens, you're liable-BIG TIME.

 

[lime4x4]

Re: what makes a tbi from a truck different then a marine setup?

so basically it's just the tag then?? I've looked at some marine tbi and mpi setups and the parts are identical to a gm setup

 

[DJ]

Re: what makes a tbi from a truck different then a marine setup?

Identical to you. If they have not been tested in an explosive chamber, they're not the same.

Your bilge is a potential "explosive chamber". Not worth the risk, in my book.

Why turn a potential accident into willful disregard. A big difference in a court of law.

As I said, if something happens, you will be in a world of hurt if someone is injured. Save a $100.00 now and pay $1M later.

Your choice.

 

[lime4x4]

Re: what makes a tbi from a truck different then a marine setup?

I'm not saying i'm going to do this was just curious. Last year a replaced my mech fuel pump with an electric fuel pump a marine one of course. Just thought it was funny that it cost me 100 bucks for a marine electrical fuel pump made by carter. I went it the local auto parts store and looked at there electric fuel pump that they had in stock for 14 bucks. My marine fuel pump had the exact same part number on it that the one at the auto parts store. Only difference was marine fuel pump had a tag that said it was coast gaurd approved.

 

[DJ]

Re: what makes a tbi from a truck different then a marine setup?

I don't doubt that.

Unfortuneately, that's the price we pay to keep the sharks (lawyers) off.

 

[JustJason]

Re: what makes a tbi from a truck different then a marine setup?

the other thing you want to think about to is how you controll it all.
MEFI fuel stratagies are different than automotive ones.
Automotive fuel strategy is all about keeping the emissions down.
Marine fuel strategies are about hi RPM maximun power, and also power reduction modes to keep an engine running, even if it's just limping.

 

[TilliamWe]

Re: what makes a tbi from a truck different then a marine setup?

Lime you are correct, the parts of a GM TBI system are IDENTICAL to the parts on a Mercruiser with TBI. I have owned a 1987 and now a 1990 Chevy van and the ONLY difference between the two systems is the Mercruiser one has black paint on it, and a spark arrestor on top.

 

[mthieme]

Re: what makes a tbi from a truck different then a marine setup?

Hmmmm.
I've rebuilt scores of Rochesters, never recall having seen any special markings or tags indicating they were marine or USCG approved or anything closely resembling the fact that were meant for marine use. Haven't run across TBI on a boat yet. Good idea though.
I've seen everything outta cars/trucks from a Packard straight 8 (what a beast!) on up in boats. The history of the Chesapeake is littered with boats built in backyards throughout it's history.

The captain is libel for his vessel and passengers anyway.

 

[Don S]

Re: what makes a tbi from a truck different then a marine setup?

I've seen everything outta cars/trucks from a Packard straight 8 (what a beast!) on up in boats. The history of the Chesapeake is littered with boats built in backyards throughout it's history.

That doesn't mean they are safe, legal by USCG standards or anything else. Just means some guy did his own thing without any consideration of safety or proper parts.

I've rebuilt scores of Rochesters, never recall having seen any special markings or tags indicating they were marine or USCG approved or anything closely resembling the fact that were meant for marine use.

On Rochester carbs, using the model number will usually tell you if it's a marine carb or not. Marine carbs are designed with no fuel bowl vents that well vent outside the throttle bores, or other way for fuel to go anywhere but inside the carb. Same with fuel pumps, if they loose a diaphram, instead of the gas going into the bilge, it goes into the carb.
The rules are there, and as stated many times in life, ignorance of the law is not an excuse in any court.

 

[mthieme]

Re: what makes a tbi from a truck different then a marine setup?

Would these be what's referred to the "J tubes" ?

 

[lime4x4]

Re: what makes a tbi from a truck different then a marine setup?

Don i never said i was doing this i wanted to know is WHAT makes them marine grade

 

[mthieme]

Re: what makes a tbi from a truck different then a marine setup?

You're safe - he was gunning for me, but we both might learn something when he returns. His delivery is like that, but he has a LOT of knowledge.

 

[Uraijit]

Re: what makes a tbi from a truck different then a marine setup?

Yup, no difference. I've got a TBI setup sitting on bubble wrap under my kitchen table right now. It'll be going into my boat over the fall. It's not a disregard for safety, because I know it's safe. It's more a disregard for buracracy. I'm not gonna pay 10x the value, for a little Uncle Sam stamp.

I plan to use the proper flame arrestors, etc.

As far as those saying that the fuel strategies are different... Not really. Not in open loop mode (which it is on a boat anyway). And if you decide you don't like the way it's running, it's a piece of cake to burn another chip for it.

 

[lime4x4]

Re: what makes a tbi from a truck different then a marine setup?

I'm a certified chevy tech with 20+ years of expereince. I would just really like to know what makes a marine part other then the sticker.Hell i could make stickers if that's all it took..lol

 

[Don S]

Re: what makes a tbi from a truck different then a marine setup?

You're safe - he was gunning for me,

I'm not gunning for anybody, the thing is, there are marine carbs and automotive carbs, there are TBI systems that have already passed USCG tests and are now used on boat. Some aren't.
Just because YOU THINK something is fine on a marine engine because of your thought processes is neither here nor there. Your opinions don't couint.
Personally, I don't keep engine parts under the kitchen table, bubble wrapped or otherwise.
No wonder so many people get blowed up and set on fire in boats. Too many out there that could care less about the regulations that try to minimize fire and explosions on boats.

 

[TilliamWe]

Re: what makes a tbi from a truck different then a marine setup?

Lime on your TBI system, the only difference from a GM truck is the fuel pump. Obviously it's in the tank on a truck, it's not on a boat. If you get the correct Mercruiser fuel pump, then you'll have exactly what Mercruiser installed on their boats with TBI. As far as the Mercruiser ignition system, you are right again. The vented distributor, with the notch cut out in the back for the modules is exactly the same as the ones on a GM truck (my 87 and 90 vans for example). Not a single difference, none.

Don has to state things by the USCG book, cause he is a professional and licensed marine mechanic. But if he doesn't know that the TBI and ignition systems on certain Mercruisers is exactly the same as on a GM truck, it's only because he doesn't work on GM trucks.

 

[mthieme]

Re: what makes a tbi from a truck different then a marine setup?

TBI is not mentioned by the USCG other than "The regulations specifically addresses carburetors, as fuel injection was not commonly available in the mid-1970s when the regulation was written."
USCG references SAE specs for further info.

"Crank the engine without starting for 30 seconds. During this period there shall be no more than 5 cc observed gasoline flow coming from the carburetor fuel bowl, vent port or any other place on the exterior of the carburetor. This test includes only external flow, not fuel flowing down the throat of a downdraft carburetor."

All the safety info is at http://www.uscg.mil

USCG annual national boating statistics include Fuel Related Fire / Explosion deaths...
2001 - 2
2002 - 4
2003 - 7
2004 - 4
2005 - 0
2006 - 1
2007 - 0

While tragic, the numbers hardly represent an epidemic.

Over 2/3 of boating fatalities are due to drowning. 90% of those were not wearing a PFD.

 

[Mkos1980]

Re: what makes a tbi from a truck different then a marine setup?

I have both setups in the garage. Part numbers are identical on all the sensors for the vortec mpi setup. One is for a 98 K1500 Vin R and the other was from a marine setup. I've never seen anything on marine fuel injection listed in the uscg book.

 

[WizeOne]

Re: what makes a tbi from a truck different then a marine setup?

Would these be what's referred to the "J tubes" ?

If you had a Holley, the answer would be yes. I do not think other brands use the 'J' tubes to direct float bowl overflow into the venturis. They are a unique and distinguishing feature on Marine Holleys.