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Dirty air cleaner

R

rickt

Member
I just put the boat away.....only had her out 6 or so times.....the last time out went to lake Erie.......poor fishing so I just cruised around.....ran out of time.......ran at nearly wot for 20 minutes or so.......I steadily lost rpm's coming in......by the time I was in, I was only getting about 3000rpm. When winterizing...I found the air cleaner very dirty with a black oilish residue...Any ideas? The engine must not be breathing correctly? I do not see a PVC valve?

Thanks in advance

PS 5.0, 305, 230hp 1984 V8
 
You will not have an Air Cleaner. This is a Flame Arrestor.
Yes, they can become dirty and restrictive.
These can be cleaned with de-greasers and/or soap and water, then blown dry with compressed air.

BTW, it is not recommended to run at WOT rpm for sustained periods.
If your cylinder temperatures ski-rocketed, resulting from detonation, damage will occur.
That may explain reduced RPM. Let's hope not!
 
So...... Compression test first. Post back here the numbers. On a warm motor all the plugs out and throttle fully down.

Keep track of the plugs what hole they came out of and when out you can read them.

We will go from there.
 
BTW, it is not recommended to run at WOT rpm for sustained periods.
Click to expand...

I do not understand this comment. Why would there be a reccommendation for not running at wide open throttle for sustained periods of time??? What is this period of time? 1 hr, 5 hrs, 24 hrs?

I could see if you were running 5500+ rpms but running 4400-4800 rpms..........I would think it could run at that rate all day long.........Kinda designed for this.......At least I think so.
 
running the engine at WOT is not recommended for continuous operation. just for a few minutes then back of to 3/4 throttle.

It you do this your engine should last a long time, run at wot all the time and you'll wear out the engine quickly . this is because the boat engines are always under a high load, this will create a lot of heat and stress on the engine..

this oily residue is from blowby gases at the flame arrestor. WOT operation on a worn engine will create excessive oil vapors which are directed into the engine intake to be consumed.

washing with low odor mineral spirits/paint thinner with the flame arrestor removed and using a parts cleaning brush will make it look new again..
 
I may have exaggerated some on WOT........WOT is 4400RPM....I was doing more like 3800-4000. I seriously doubt I have any mechanical problems......The boat is in storage...so I will have to wait until spring.....It was truly "choking out"...When I tried to start the engine for winterizing..it was flooded immediately. I took of the flame arrestor....thanks for the nomenclature correction....I did know that....anyway it started right up and sounded fine.

Do I need to clean it more often...I mean obviously I do....but is this normal? Should I be looking at something different in maintenance?

Thanks
Rick
 
As far as WOT operation is

Yes it will wear the engine out sooner than later but I dought it would be the answer to his problem..................Just sayin.......

Also asking a question when your boat is in storage is kinda useless as it iwll be 6 months before you will be able to run it again...........wait till then and after a fresh lake test to see what is going on....
 
rickt said:
Do I need to clean it more often...I mean obviously I do....but is this normal? Should I be looking at something different in maintenance?
Click to expand...
I had one boat where the engine cover insulation foam stuff was rotting (in behind a baffle board.... it was all vibrating out and getting sucked onto the arrester)
normal cleaning interval would be once or twice a season
 
kghost said:
As far as WOT operation is

Yes it will wear the engine out sooner than later but I dought it would be the answer to his problem..................Just sayin.......

Also asking a question when your boat is in storage is kinda useless as it iwll be 6 months before you will be able to run it again...........wait till then and after a fresh lake test to see what is going on....
Click to expand...
I did not suggest that this was/is an answer to his problem.
When I hear someone say that they were running at WOT, I always post that comment.
It is not wise to sustain WOT RPM, period!

kghost said:
Just wipe it with a clean shop rag once in a while and you will be good
Click to expand...
Unless you submerge this in some sort of degreaser, you will NOT completely remove the oily/dirty build-up from between the thin metallic plates.

.
 
If you have fine black dust on the front side of the arrestor then suspect the drive belts are dryrotting and need to be replaced. The dust will collect everywhere on the front of the engine.
 
To quote the question...........AGAIN

>>>>ran at nearly wot for 20 minutes or so.......I steadily lost rpm's coming in......by the time I was in, I was only getting about 3000rpm. When winterizing...I found the air cleaner very dirty with a black oilish residue...Any ideas? The engine must not be breathing correctly? I do not see a PVC valve?<<<<

So to all the advice on how to operate a boat.................

He developed a issue while running at wot on his way to shore/dock.
His only observation was a dirty flame arrestor.
His question WAS could this affect his condition.

A answer or reccomendation of not running WOT for sustained periods of time has NO revalence to this!! AT ALL!

All flame arrestors get a black oily film on them. and as a simple method of cleaning a clean shop rag will surfice to clean it off. Of course a thourough cleaning requires solvent and compressed air cleaning.

I have only seen a couple flame arrestors over many years have any affect on engine performance. And the result was a very rich running condition as if the choke was full on.

JMHO
 
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