150 hp Force Fuel Carb Question.......

brinker232

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Is it normal for the carbs to "Spray" or "Mist" fuel out the front of them when idling?
 

pnwboat

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Re: 150 hp Force Fuel Carb Question.......

I wouldn't think so. The flow of the fuel mixture and air should be in one direction.....into the engine. Does the motor run OK at idle speed?
 

Frank Acampora

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Re: 150 hp Force Fuel Carb Question.......

The 150 five cylinder engine has crankpins spaced at 72 degrees apart. The top and bottom carbs service two cylinders each while the middle carb services only one.

If crankpins were 180 degrees apart the airflow would be more uniform BUT the center carb has a pulsing flow while the top and bottom are not too bad.

Reeds take a while to close so during crankcase compression some of the inducted mix is blown back into the manifold. Top and bottom carbs do not have enough airflow through the manifold to retain this "spit back" while the center carb, which sees true pulsing airflow, will be worse.

The engine should have come equipped with black plastic carb covers to capture spit back.

So: Simply put---YES it is normal for the 150 carbs to spit back some fuel while running. It is not normal to spray a lot! If spray is excessive look for bent or broken reed petals.
 

brinker232

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Re: 150 hp Force Fuel Carb Question.......

Thanks for the info Frank! The middle one is the one doing it. It Idles good for about 30 sec or so before it loads up and dies and I can't seem to over come this so I was wondering if the spray might have anything to do with it. Thanks Again!
 

jerryjerry05

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Re: 150 hp Force Fuel Carb Question.......

Really need to know what year and model and serial#???
Do a compression test.
Then pull the carb and check the reeds.
I might have a set you can get.
The blocks might be different but the reeds should be the same??
 

brinker232

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Re: 150 hp Force Fuel Carb Question.......

Sorry guys.....

Its around a 1990 US Marine Force 150
WP_000320.jpgWP_000323.jpgWP_000324.jpgWP_000328.jpg
 

jerryjerry05

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Re: 150 hp Force Fuel Carb Question.......

The sticker is on the transom mount.
If it's gone? Then under the power packs and coils might be a foundry stamp.
If no then under the rear cover is a foundry stamp.
Yes my reed plates will work if you need them.
 

brinker232

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Re: 150 hp Force Fuel Carb Question.......

WP_000368.jpg
Carb one is blowing out a milky colored fuel mixture. I have a video, just waiting for it to upload so I can attach it.
 

brinker232

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Re: 150 hp Force Fuel Carb Question.......


Any Thoughts?? JerryJerry is this something that has to do with the Reed Plates you were talking about? Why is it milky looking?
 

pnwboat

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Re: 150 hp Force Fuel Carb Question.......

Seems to blow out even more when you hit the throttle. I would suspect the reeds. Like Jerry mentioned....might also do a compression check if you haven't already done so.

Milky colored fuel mixture could be water contamination.

Is that gas leaking out of the bottom carburetor right at the end of the video?
 

brinker232

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Re: 150 hp Force Fuel Carb Question.......

Seems to blow out even more when you hit the throttle. I would suspect the reeds. Like Jerry mentioned....might also do a compression check if you haven't already done so.

Milky colored fuel mixture could be water contamination.

Is that gas leaking out of the bottom carburetor right at the end of the video?


I have a "see-thru" water filter in the fuel line and it's clear. Where would the water be coming from? Yes, that is fuel. That is what dumped out of the plastic carb covers when I tilted the motor up. Where are the "Reed Plates?" Ive never heard of them until Jerry mentioned it. Compression Check is normal across all 5 cylinders.
 

pnwboat

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Re: 150 hp Force Fuel Carb Question.......

The reed plate assy sits underneath each of the carburetors. Basically it's a row of thin metal flaps that allows the air/fuel mixture sucked into the crankcase through the carburetor to only flow in one direction. There's a couple of folks on this forum that have 5 cylinder 150HP motors. Maybe they can chime in and give their thoughts on the blow back as seen in your video as compared to their motors. I recently did some carburetor adjustments on a 150 HP motor and I don't recall seeing any blow back like what I see on your motor.

Reed plate assy consists of item numbers 27 - 31 in the diagram below. The reed petals (item 28) are what go bad, get bent or broken, and are replaceable.

Mercury, Mercruiser, Force, etc. - FUEL INTAKE SYSTEM - 150 H.P.

Not sure I would concentrate on the milky colored stuff blowing out just yet. If it is water contamination, you will most likely see the milky mixture sitting in and around the reed plate assy....maybe in the crankcase area too when you take off the carburetor and adapter plate. Most likely source would be a head gasket or exhaust cover gasket.
 

jerryjerry05

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Re: 150 hp Force Fuel Carb Question.......

The blow by is probably a bad set of reeds,I got them if you need. You pay postage.
The milky? That's possibly the fuel recirc system?Picking up moisture from he bottom of the motor.
You need to remove and check for clogged orifice's. 2 dog bone looking things on the stbd. side
Possibly the head gasket?not really.That would have water/rust on the plug.
The water jacket is more likley. The gaskets are about $80 So look up a kit on e-bay and get a set with the head gasket too.
FG1027-2 Part#

Send a PM if you need the reeds.
 
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