Model # 507F4A US Marine 50 hp

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 20, 2004

• #1

Ran fine till I put it in Gear. Get to about 1/3 throttle and it boggs down. Runs Great at Idle. Any Ideas? Also do you know where i can get a manual for this US Marine engine?<br /><br /><br />Thanks

 

eurolarva

Rear Admiral

Joined

Jun 24, 2003

Messages

4,182

• Jul 20, 2004

• #2

Re: Model # 507F4A US Marine 50 hp

That model number you gave is for a 1984 force outboard. I am not sure on my history but I believe us marine was taken over by mercury and now it goes under the force name. Here is a link for a service manual. Force manual <br />Mercury stocks parts for this motor. If you choke it when shifting does the motor improve? If it does you probably have a fuel related problem. You should start with fresh gas mixed 50 to 1, rebuild the carb and replace the diaphram on the fuel pump to start with. If that dont fix it post what you did and what the current symptoms are.

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 21, 2004

• #3

Re: Model # 507F4A US Marine 50 hp

Thank you. Will do it today and get back to you tonight

 

C

CoachHolland

Petty Officer 2nd Class

Joined

Apr 20, 2004

Messages

165

• Jul 21, 2004

• #4

Re: Model # 507F4A US Marine 50 hp

Check your spark on each cylinder as well. At idle you won't always notice a miss. Also, check your plugs and see if they are clean or not. Clean plugs with water indicates a possible blown head gasket. Clean with gas indicates no fire. Could be weak spark or too rich fuel.

 

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nmbr1ddy

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Joined

Jul 19, 2004

Messages

15

• Jul 21, 2004

• #5

Re: Model # 507F4A US Marine 50 hp

Replaced both plugs. good fire on both. Idles well still trying to find the diaphram and reuild kit at a locaL NAPA in stock

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 21, 2004

• #6

Re: Model # 507F4A US Marine 50 hp

Got the rebuild kit and diaphram ordered. After checking the engine the top of the coils look like they are carcked. Local NAPA dosent have a coil listed for this engine. Can you anyone tell me the part # for the coils? I can send a picture if you need it

 

C

CoachHolland

Petty Officer 2nd Class

Joined

Apr 20, 2004

Messages

165

• Jul 21, 2004

• #7

Re: Model # 507F4A US Marine 50 hp

Blue coils or do you have the black ones?<br /><br />You can order new from seilermarine.com or check out ebay for a used set. Look for the username "outboardpart" and tell him what you need. Great price and I've done business with him. The stuff he sells works great.

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 21, 2004

• #8

Re: Model # 507F4A US Marine 50 hp

Black

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 23, 2004

• #9

Re: Model # 507F4A US Marine 50 hp

Rebuilt The carb and Fuel pump, Then Decarbed Engine. Still idles great. Still No Power when appying throttle past 1/3. Seems like a car with the timming advanced to far.

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 23, 2004

• #10

Re: Model # 507F4A US Marine 50 hp

Also applying choke make it worse.

 

eurolarva

Rear Admiral

Joined

Jun 24, 2003

Messages

4,182

• Jul 23, 2004

• #11

Re: Model # 507F4A US Marine 50 hp

YOu might want to replace that cracked coil. If choke makes it worse it is probably electrical.

 

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nmbr1ddy

Cadet

Joined

Jul 19, 2004

Messages

15

• Jul 24, 2004

• #12

Re: Model # 507F4A US Marine 50 hp

Can you tell me how to set the timing on this model?