fuel

I'm working on a merc classic fifty 45hp for a customer. I have never worked on one of these before.I work mostly on yamaha outboards.Anyway,<br />the motor runs great at idle but will not run at any other speeds.On these motors when u prime the engine up to where the primer bulb gets tight should gas come out of the carb throats &<br />main air jets. The only time i see this is when<br />the needle is stuck open or when the float is cracked and will not close needle to seat.Both carbs are doing this is why i am not sure about going into them yet. If anyone can help please reply.

Re: fuel

On many of "those" older motors it is possible to flood past the needle/seat if the bulb is squeezed hard enough.<br /><br />The carbs should not "overflow" during operation.<br /><br />Sounds as if you may have a starvation condition. That could be verified if you easily squeeze the bulb while it's not making power. If it makes power better while giving it a bit of a squeeze look for poor fuel pump operation or an air leak in a hose or fitting between pump and tank.<br /><br />It's also possible to have dirty fuel filters at the tops of the float bowl covers, or partially plugged jets. Those are best checked by actual disassembly and visual inspection.<br /><br />If it stumbles worse when you give it a squeeze it must have been flooding all along.<br /><br />Check the compression just to verify you are not "kicking a dead horse"<br /><br />And make sure the plug wire are installed correctly, as they will run at idle on two cylinders reasonably well. Some magneto distributor caps had more than one set of firing orders embossed in them.

Re: fuel

I have the same motor.<br />timing should be set at 7-9 Deg BTDC with engine in gear. ( most other Mers can run at 5deg ATDC apparantly,) but this model has those specs for its ignition and must be in gear and in a test tank!<br /> Max spark advance is 30 Deg BTDC in gear at WOT in a test tank<br />Primary pickup is done by loosening the 2 actuator plate screws whilst the engine is running in gear at 7 -9deg BTDC, turn the actuator plate until it just touches the primary pick up arm on the carbs. Tighten the screws and return to idle,<br />Hope this helps

Re: fuel

I went into the carbs and found that they have cork float bowl gaskets which over time started breaking up and getting into the carb.Also springs on the needle were worn out..Just thought i would let you guys know what i found.<br />Work hard and Fish harder......Injectordriver