flame arrestor

[ridesapaint]

My '96 Sea Ray 175 brxl has the 4.3L 160hp, and the plastic flame arrestor cover is cracked. I was looking to replace it, yes for cosmetic reasons, but it's much cheaper to put a really fine K&N performance flame arrestor/filter on it. And, it will even have some more breathing capacity.

Are those two cheap hoses going into the stock arrestor needed? They don't even go inside the arrestor, but just dangle up to them. I think the new one might have connectors if I get the right arrestor. Which one do I need? I don't know the throat size or clearance, but I am pretty sure the clearance is not going to be an issue.

Jerry

 

[mkast]

Re: flame arrestor

When the engine is running, a low air pressure area (less then ambient) is present at the flame arrestor.
Those "cheap hoses" are only needed when the engine is running.
Crankcase vapors (higher then ambient) are routed from the valve covers to the flame arrestor, when the engine is running.
You don't need them, but your engine might.

 

[abj87]

Re: flame arrestor

YES you need the lines from the valve covers, as said before they allow blow-by gases to be returned to the engine. Without them you will be filling your engine room with smelly,oily, exhaust gases.

 

[slasmith1]

Re: flame arrestor

The K&N filter is not a marine approved flame arrestor. The first time you get stopped for a courtesy inspection you will find out. Or when you blow up your boat. The flame arrestor is required on marine applications because the motor is run in an enclosed space that can accumulate vapors that can explode when exposed to an ignition source such as an engine backfire or non ignition protected electrical components. there are many posts you can find here that discuss why not to use automotive parts on a boat. the best of those reasons is simple saving a couple bucks is never worth risking someones life.

EDIT: The filters on K&N web site do not have the coast guard stamp on them. I see they Identify them as a flame arrestor but with oil soaked cotton in them it still looks shady to me I would just replace the correct cover.

 

[180shabah]

Re: flame arrestor

The K&N's are marine approved - the filter media surrounds the all metal flame arrestor. But justlike on your car(or any engine) a filter of any kind decreases flow. In a marine environment there is very little particulate matter to filter. In fact, every time I clean my FA the biggest offender is carpet fibers, and just a few of them. With a 2bbl carb you have a smaller "throat" that will limit your choices. At best you could gain 1-2hp, a difference that you will never notice. If you are worried about the cosmetics - toss the plastic cover and polish the flame arrestor you already have. Then send me a check for $50 to cover the difference from your planned expenditure.

 

[ridesapaint]

Re: flame arrestor

OK I did a lot of homework and read several threads, and found some great info from searches on the web.
The throat size is the same from 3.0L through 5.7L on the mercs and the only difference for application is the height of the Arrestors, taller allows more air. The only other issue will likely be clearance in the engine compartment. My boat has lots of room, so I will be going up one size for the actual replacement.
Yes, the K&N flame arrestors are definately USCG approved. It has an oiled cotton gauze and epoxied screen filter element. I am talking about the FA not the auto air filters. Plus, I will spend a lot of time around the desert lakes like Powell, Roosevelt, Apache, Navajo, and Elephant Butte in Arizona and New Mexico this summer, so I plan on protecting my engine if I can. If there is no dirt on the water then I will never have to clean it or replace it. I will get the pretty stainless K&N and the vent hose adapters, and replace the cheap plastic hoses with something a tad more stout. I'll take 2-3hp and a ounce or two of fuel/hour every chance I can. What can I say, I like my boat a lot and want to keep it nice inside and out. The next part will be to find the right prop for her.
Thanks everyone.
Jerry

 

[180shabah]

Re: flame arrestor

Your anticipated gains are optimistic - any benefit you may have gained by increasing the size of the FA will be negated by the addition of the filter media around it. Obviously, I can't tell you how to spend your money, but throwing money away just to look cool never made any sence to me.

If you are interested in making real improvements underneath that pretty new FA then consider a 4bbl upgrade. That will be good for a 20hp gain at the prop from 155 to 175. Vortec heads will net you 30hp at the prop. combine the two with a performer aluminum intake manfold and you will have an honest 205-210hp at the prop. 50-55hp WILL make a difference in a 16' hull.

 

[ridesapaint]

Re: flame arrestor

The whole idea is that the replacement FA cover is almost $200 from what I can find. The K&N for the V8 will breathe a lot better than the stock FA. I am looking at the Mallory also, but I like the filter factor of the K&N. If you spent anytime in the desert in late spring or early summer when winds are 50mph, and seen dust devils cross the water as I've seen you would understand my viewpoint. It's a less expensive alternative by a hundred bucks than buying the replacement cover even if the airflow improvement is marginal. I am really looking forward to a new prop and will have to wait till I get the boat in the water to figure out which prop to choose.

 

[180shabah]

Re: flame arrestor

Prop selection will be fun - good excuse for some WOT runs

 

[Windykid]

Re: flame arrestor

OK I did a lot of homework and read several threads, and found some great info from searches on the web.
The throat size is the same from 3.0L through 5.7L on the mercs and the only difference for application is the height of the Arrestors, taller allows more air. The only other issue will likely be clearance in the engine compartment. My boat has lots of room, so I will be going up one size for the actual replacement.
Yes, the K&N flame arrestors are definately USCG approved. It has an oiled cotton gauze and epoxied screen filter element. I am talking about the FA not the auto air filters. Plus, I will spend a lot of time around the desert lakes like Powell, Roosevelt, Apache, Navajo, and Elephant Butte in Arizona and New Mexico this summer, so I plan on protecting my engine if I can. If there is no dirt on the water then I will never have to clean it or replace it. I will get the pretty stainless K&N and the vent hose adapters, and replace the cheap plastic hoses with something a tad more stout. I'll take 2-3hp and a ounce or two of fuel/hour every chance I can. What can I say, I like my boat a lot and want to keep it nice inside and out. The next part will be to find the right prop for her.
Thanks everyone.
Jerry

Yeah I have a K&N marine filter, problem the coastie had with it, is it does not have a Coast Guard stamp or tag on it. So I couldnt pass inspection with it.:redface:

 

[Don S]

Re: flame arrestor

Just out of curiosity, what are we actually talking about here for real. In the picture below, are you referring to A or B?
1 The flame arrestor is not plastic.
2 The flame arrestor cover that is plastic (A) has nothing what-so-ever to do with what the flame arrestor does. All it does is keep water off the carb and electrical parts under it
3. The Flame arrestore (B) is metal and the same one is used on V8 engines to. Seems enough air gets into a V8 so would suspect there will be plenty of air flow for a V6.

 

[ridesapaint]

Re: flame arrestor

Don, I am talking about all of it. My cover (A) is all busted up and the ones I am finding are either junk or overpriced, and they are kinda ugly. My flame arrestor (B) is also pretty much looking like its 13 years of age. The rest of the engine and boat are pristine, and has 64 actual hours on it. Yup, 64 hours. It was a garage find from a lady who donated it to a non-profit, I got an inside tip on it and snatched it up, right after they rebuilt the lower unit since it was apart for some seal or something. The carb was also rebuilt.

For the price of covering the ugly flame arrestor (B), I can replace the flame arrestor (B) with one that looks and performs better than both (A and B).

Whats the big deal? I just want it to look as nice as the rest of the boat, and it will look great with a Mallory or K&N flame arrestor, and will breathe easier to boot.

Thanks for going to the trouble of posting the diagram.

Jerry

 

[rodbolt]

Re: flame arrestor

trust me its NOT going to breathe any eaiser as a stock V6 just doesnt suck huge quantities of air to start with.
the reason is the USCG gets to design how close the wafers are for the flame arrestor desighn.
what it does is in the event of a carb backfire its designed to disperse and extinguishe any flame leaving the carb before it exits the OD of the flame arrestor, hence the term, flame arrestor.

now as far as looking cool? thats one mans dream and anothers dog.

2 summers ago I had a customer come in asking for a polished SW series prop.
I asked him what was wrong with the standard black painted SS prop that was maybe 4 months old.
he said nothing, just all my other neighbors have their boats on lifts and it looks cool.
475 for the prop and an hour to install it and he was cool.
but I do understand that the cost of the stuff from various manufactures can get on the ridiculous side.

 

[JustJason]

Re: flame arrestor

an hour to install a prop rodbolt??

 

[rodbolt]

Re: flame arrestor

hey, wasnt me.
our shop has a one hour min shop charge.
owner figgered if the customer was cool enough for me to go down on the dock and do an in water prop change he was cool enough to get the minimum.
but I will admit it was the nuttiest,or among them, things I have seen.
remove an almost new black painted SS Yamaha prop for a highly polished salt water series just cause it looks cool on a lift ?
absolutly no performance gains, simply looks cool.

 

[wkb2460]

Re: flame arrestor

Seems to me his mind is made up.
If it were me , I'd stick with the coast guard approved metal arrestor.

It may look pretty, but if you or your family blows up, you won't be able to enjoy the boat.

 

[Maclin]

Re: flame arrestor

My 18 year old flame arrestor scrubbed up pretty good, not much to wear out on them.

I think the cover is important, it is on mine anyway, keeps errant water flow off of the carb and the distributor, like when/if a cover fails or it gets caught out in weather before the boat's cover can get on. My engine box can let water in at the back and the f/a cover is right there protecting the distributor.

 

[Don S]

Re: flame arrestor

I don't know what the big deal is, he likes the looks of the K&N Flame arrestor, compared to the OEM So.................. Big deal.
Let him use it instead of OEM.
The K&N FA's are legal and are actually CG approved flame arrestor.
May not help anything, but it won't hurt anything either.

http://www.knfilters.com/marine/flamearrester.htm

 

[ridesapaint]

Re: flame arrestor

Seems like some of you are just greasy-fingered old farts with little pride in their boats, and even less in others' boats. I bet your old 27 inch TV and VCR is just fine too. You need to get out more.

One email to the website, with one or two simple questions, and K&N was speedy in responding with all sorts of honest testing results and specifications that directly conflicts with the grumpy old men--and you know who you are--who think the noncompliant aftermarket flame arrestor/filter will have no benefits over the stock.
They also provided pictures and detailed descriptions of where "CG Approved" can be found on every single piece of the FA; on the cover, on the base, stamped into the urethane rubber gasket that holds the epoxy shell ... because the Coast Guard engineering actually assists in the parts' design, and regulate before they go into production. I was amazed at how fast, detailed, personalized, and professional they were.
I like how many options I have, and usually I enjoy forums because most people are friendly and supportive, with constructive criticism. It certainly is not about saving $45, and I will never treat a boat like an old Chevy truck.
As far as the nay-saying grouches, you can EDIT: >>>>>>>>>>>>

 

[bigbob_FTW]

Re: flame arrestor

Do whatever floats your boat (pun intended).