1975 mercury 150 outboard

Froggin

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Feb 3, 2014
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Hi guys new to the forum and have a question on this outboard engine i just had fixed that was sitting for probably 2yrs before i bought the boat its on....needed a distributor first and i repaired it due to no fire issue. It wouldn't pump water after getting it started so i had waterpump, and all carbs&floats and fuel lines redone. Put it in water yesterday and boat has no fuel tank so i used a portable tank w/bulb. Idles nicely and after going in gear throttle gets little response. After checking all my wires and all everything is good. Had my buddy with me and we had throttl forward i figured imma pump bulb make sure fuels getting through. The boat picked up and ran like a scolded dog but its only while i constantly pump bulb then about 4k rpm the bulbs outta fuel and i just keep pumping it keeps going till boggs out at 5k and above. Is this tanks fuel line to small or the cap not loose enough for the engine to keep sucking what it needs? Im not sure if there was electric fuel pumps on the inboard tanks? Any help appreciated thanks guys.
 

gbrowne9

Petty Officer 2nd Class
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Jan 1, 2010
Messages
102
Re: 1975 mercury 150 outboard

replace the fuel pump gaskets and valves,it comes in a kit for 20 bucks+/-.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: 1975 mercury 150 outboard

No, that motor has a mechanical fuel pump, even with permanent fuel tanks. Fuel line should be at least 5/16" ID. 3/8" ID is better. Rebuild the fuel pump. Make sure the vacuum lines that operate the fuel pump are good.

Richen the idle mixture 1/8 of a turn, if the above doesn't work.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,032
Re: 1975 mercury 150 outboard

????????--Mechanical fuel pump ???---------It came with a typical pressure pulse diaphragm / check valve fuel pump.----Repair kit about $20 as posted !-----These are pressure pulse pumps and not vacuum pumps.--The pressure pulse is more pronounced then the vacuum pulse.
 

Chris1956

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Mar 25, 2004
Messages
27,030
Re: 1975 mercury 150 outboard

Racer, That pump is not electrical as asked by the OP, hence my statement that it is mechanical.
 

Froggin

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Feb 3, 2014
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Re: 1975 mercury 150 outboard

Ok guys i bought the kit to repair fuel pump should be here friday. If weekend weather permits will give it a go. Thanks for the help. Anyone know by chance what kind of permanent fuel tank went in a 1996 hydra sport 17.5' bass boat? Or should i just go with a portable tank but take up some rear deck space.
 

Chris1956

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Joined
Mar 25, 2004
Messages
27,030
Re: 1975 mercury 150 outboard

You should see the built-in tank, if it had one (likely). Look for the fuel fill and vent. Normally Hydra-sports boats came with a Johnnyrude motor, so fuel fittings will be different.
 

Froggin

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Feb 3, 2014
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Re: 1975 mercury 150 outboard

The built in one was removed by some owner of the past. Have to install a new one.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: 1975 mercury 150 outboard

Likely the original fuel tank was a standard one made by Tempo or some other manufacturer. Maybe you can measure the tank well and match one up. Skyline was the brand of tank used on my SeaSwirl. Not sure they are still in business.
 

Froggin

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Feb 3, 2014
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Re: 1975 mercury 150 outboard

Well i was in luck yesterday. My buddies dad has 2 old boats laying around he cut the sterns top piece off a bayliner and said he thinks theres a tank in it that would fit. We walked out to the boat and pulled it out. Looks brand new still. And fit exactly in place in mine..not bad for free i just have to get new hoses to hook it up and a few things to secure it. Saves me some money which is good. Thanks for all the help.
 
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