Venting I/O engine compartment necessary after towing?

[martymudskipper]

I have a new to me Aquasport 222 with 5.7L Volvo I/O. I've read lots about boats with I/O exploding when the boat is re-fueled and the engine started without first running the blower. What if the boat is re-fueled while on the trailer then the boat is towed to the launch. The vents on the engine compartment are configured so fresh air enters the engine compartment and the old air exits when the boat is moving. Is this sufficient to vent the engine compartment or do I still have to run the blower? Should I run the blower before each re-start during the day?

 

[ziggy]

Re: Venting I/O engine compartment necessary after towing?

my notion is that the answers should be yes, and yes.

i understand what yer saying about moving down the hiway. but the rule is run it for 5 min. prior to start + have a sniff i think. refueled or not. i'd think especially after refueling.....i do this even though it just came off the trailer.....start the blower while yer preping to launch. launch, sniff and go.....

yep, on the water after ea. stop. blower for 5 min. is recomended...

do i do it every time on the lake....after a or 2 min. stop.........i ain't saying.....but after a hour stop. yes. for sure........

 

[Drowned Rat]

Re: Venting I/O engine compartment necessary after towing?

What Ziggy said. If you happened to have a fuel leak or spilled fuel, it wouldn't take long to develop enough explosive vapors to ruin your day.

 

[tommays]

Re: Venting I/O engine compartment necessary after towing?

It is the FIRST thing i do when i get to the ramp EVEN before i put the PLUG in


I find it usefull to get the boat ready the same way everytime as it becomes so routine you do NOT forget something inportant like Running the Blower



Tommays

 

[rndn]

Re: Venting I/O engine compartment necessary after towing?

Why take the chance?? It makes no sense to try to not vent when it only takes a few minutes and doesn't cost a dime.

 

[Wotam]

Re: Venting I/O engine compartment necessary after towing?

"Why take the chance??"

Ditto. It only takes a few minutes to be safe... most accidents occur when people get in a hurry and 'cut corners', even when they know they shouldn't.

 

[oops!]

Re: Venting I/O engine compartment necessary after towing?

fuel fumes are heaver than air and hug the bilge.
air movement is a funny thing and you couldnt be sure that the top mounted engine vents would move enough air to compleatly remove the fumes.

also if there is a small (or large) fuel leak that you cant see i wouldnt take long to "re fume" the area

safety is allways best.

cheers
oops

 

[orion25]

Re: Venting I/O engine compartment necessary after towing?

Run the blower for at least 3 minutes before you start - no matter what you were doing before starting. Blowing a few battery amps is much better than blowing your entire boat (and possibly yourself).

 

[ziggy]

Re: Venting I/O engine compartment necessary after towing?

Run the blower for at least 3 minutes before you start

in a boater safety class, they'd instruct ya to run it for 5 min.

this number has been increased from 4 min. just a couple years ago.

on a plaque by my ign. switch in my boat. it states to run it for 2 mins. my boats a 1975.

i think the point is that it's very important to run the blower and to be a safe boater, ya really need to run that blower for 5 min. appearently since 1975 someones (uscg i assume) found that 2 mins. ain't long enough, 4 aint long enough. so now it's 5.......

a side note. i also think the last rule. that ya do anything to prevent an accident, is the only rule that would over ride this blower rule..... i've had to do this at least 2 time. once for a cruiser wake that was overtakeing me from astern that most likely would have washed over my transom. and once thru my own neglegence on the river. i was about to float into a green can sideways......only missed it by a sec. or two.......both times i fired up w/o out a blower period. both times i also thought i was in a very dangerous situation for possibly takeing on much water......

 

[tashasdaddy]

Re: Venting I/O engine compartment necessary after towing?

also run blower when idling, or cruising very slow.

 

[Caveman Charlie]

Re: Venting I/O engine compartment necessary after towing?

Is it best to run the blower with the engine cowling open or closed?

I often open the engine cowling up as soon as I get to the dock. But, I sometimes wonder if it's not better to leave it closed so the air being drawn into the blower has to go down the hoses into the bottom of the bildge.

 

[oops!]

Re: Venting I/O engine compartment necessary after towing?

hey wait a minit!!!

do blowers suck the fumes out.

or blow new air in?

mine sucks fumes out, makes sence to me.
is it backwards

 

[ziggy]

Re: Venting I/O engine compartment necessary after towing?

do blowers suck the fumes out.

yep. low pressure at the end of the hose in the bilge. high pressure blowing out of the aft faceing vent on the deck.....

Is it best to run the blower with the engine cowling open or closed?

i'd think it'd be best with it open. based on the notion that when ya fuel, ya close all hatches. after fueling ya open them all and vent for 5 min..... sniff low and go, assuming ya don't detect fuel vapors....

also run blower when idling, or cruising very slow.

yep, that's sound advise.......

 

[dmcb]

Re: Venting I/O engine compartment necessary after towing?

Well it is sucking air from your bilge but to replace that air some is sucked in via the vents.
Btw, have you noticed the vents on one side face one way and the opposite way on the other.
Or they should if installed correctly.
When running, the air is forced in one side and goes out the other.
Doug

 

[Caveman Charlie]

Re: Venting I/O engine compartment necessary after towing?

i'd think it'd be best with it open. based on the notion that when ya fuel, ya close all hatches. after fueling ya open them all and vent for 5 min..... sniff low and go, assuming ya don't detect fuel vapors....

QUOTE]


Ya do?? That's good to know. I haven't had to add fuel yet. I'll be dumping it in out of cans most of the time anyway.

 

[Mischief Managed]

Re: Venting I/O engine compartment necessary after towing?

I think it's best to leave the hatch closed when operating the blower. This allows the inlet vents to most effectively displace the gas fumes that the blower is drawing out, right at the source. Your vent system is designed to work this way, why mess with it? That said, my boat has an electrically raised engine hatch and I'm not about to operate it before running the blower.

Leaving the hatch closed also can help ensure the gas fumes are removed in the off chance the inlet hose has fallen off the blower. The only inlet air in the engine compartment comes into the bilge first, if the hatch is closed. This air can help disturb and mix any ligering gas fumes and the blower will at least have a fighting chance of pulling the fumes out. With the hatch open, the blower with a missing hose will likely draw air through the opne hatch and leave the bilge air undisturbed.

In addition to running the blower, it's always a good idea to put your face right in the blower's output and take a nice long sniff. You can easily detect gas fumes this way and you will get to know what the air normally smells like. Odd engine smells can be early signs of a mechanical problem and you may save yourself some aggravation and money by identifying a problem early.

 

[Nandy]

Re: Venting I/O engine compartment necessary after towing?

that is the reason why I cant have a i/o in my fishing boat. I easily start my motor over 10 times in a full day of fishing. That would be nearly an hour diluted in the "blowing" process. In not saying is not needed, but for a fishing vessel the way I fish, no way...

 

[ziggy]

Re: Venting I/O engine compartment necessary after towing?

That said, my boat has an electrically raised engine hatch and I'm not about to operate it before running the blower.

hum, well mines a manual dog house. complete with a bungee cord holding it in place. i only open mine on the fisrt start of the day after launching, after the blower. gotta have me a sniff......

In addition to running the blower, it's always a good idea to put your face right in the blower's output and take a nice long sniff.

i do that too............but,

Leaving the hatch closed also can help ensure the gas fumes are removed in the off chance the inlet hose has fallen off the blower.

the vapors are in the bottom of the bilge. most blowers are just under the deck, up high.......i don't know that it'd get enough flow to bring the vapors up from the bottom...... opening the hatch may lead to the discovery of the disconnected bilge blower hose. + if hatchs open after fueling helps rid those areas of possible fumes. it seems it'd hold true for the bilge too.....just my thoughts anyways...

i got my statement reguading open or closed hatchs while fueling from chapmans.........the question is, is one way better or another, not nessesarily while fueling....i don't know. mine is usually closed too...but for which is better. i aint gonna disagree with chapmans...

I'll be dumping it in out of cans most of the time anyway.

i use 5 gal cans too...... i usally make a bigger mess than if i'd go to the pump.......

 

[bruceb58]

Re: Venting I/O engine compartment necessary after towing?

I turn my blower on the minute I get to the launch ramp and doesn't get turned off until I am up to speed.

A more important thing to do is to open the engine hatch and inspect for fuel and water leaks before and after you start your engine.

 

[Scaaty]

Re: Venting I/O engine compartment necessary after towing?

Oh ferchrissakes..on start, and not on plane, run the darn blower....no if's, ands or buts ...why would you NOT want too..?