Johnson Sailmaster 6ph only runs while manually pumping

[jcm02]

Hi everyone. This is my first post here. I stumbled across this site while googling my problem and repeatedly got sent here.

I am working on a Sailmaster 6 h.p. on a boat that was recently dontated to a school where my wife teaches. I am not sure of the year model. It is on a 1984 boat.

I believe the boat and motor have been sitting for 2-3yrs.

I cranked it for the first time yesterday and it cranked with very little trouble. I soon realized though that the only way to keep it running was to give the primer pump on the gas line a squeeze every minute or so. If I do that, it runs fine. However, if I fail to squeeze the pump, the pump loses pressure and the engine soon dies.

I assume the problem is either the fuel pump or the carb (all of the lines look good so I assume they are not the problem).

Can anyone give me any advice as to which area the problem is in and some advice on fixing it? Thanks!

 

[ftltony]

Re: Johnson Sailmaster 6ph only runs while manually pumping

Find the fuel pump and check the fuel pump diaphram. It could be ruptured and its an easy, inexpensive fix for the problem... if that is the problem!!!

 

[tashasdaddy]

Re: Johnson Sailmaster 6ph only runs while manually pumping

prime the fuel line, with the bulb, disconnect the fuel line at the carb. pull the rope a couple of times, you should get squirts of gas, if so you have a dirty carb. need model # of motor to get proper carb kit.

 

[jcm02]

Re: Johnson Sailmaster 6ph only runs while manually pumping

Thanks guys for the quick, helpful responses. I will try the two recommendations that you made (diaphram and disconnecting line from carb) Saturday and see where that leaves me.
I am not sure what the model number is so I'll also check that in case the diaphram fix doesn't do it.
Thanks again.

 

[ftltony]

Re: Johnson Sailmaster 6ph only runs while manually pumping

By any chance, and just for the sake of asking, is the gas that you are pumping into the motor just as old as the time the boat has been sitting for....?

 

[Xcusme]

Re: Johnson Sailmaster 6ph only runs while manually pumping

Jcm02.....FYI ...by following Tashasdaddys' advice you ARE testing the fuel pump diaphram. If you don't see fuel being pumped, replace or rebuild the fuel pump.

 

[jcm02]

Re: Johnson Sailmaster 6ph only runs while manually pumping

By any chance, and just for the sake of asking, is the gas that you are pumping into the motor just as old as the time the boat has been sitting for....?

No, the fuel is fresh.

 

[jcm02]

Re: Johnson Sailmaster 6ph only runs while manually pumping

One last question...
Is anyone aware of a site that has diagrams/schematics of the fuel pump and carb for this engine? I've been searching for quite some time and cannot find one.

 

[Xcusme]

Re: Johnson Sailmaster 6ph only runs while manually pumping

Try here:

http://shop2.evinrude.com/ext/index.aspx?s1=4f76ddb5db91185fdbe9e919aa8784de

 

[BillP]

Re: Johnson Sailmaster 6ph only runs while manually pumping

So you HAVE unscrewed the tank vent right?

Ok, a couple of thoughts. First, air leaks in the fuel deliver system can drive you nuts chasing them but they are the easiest to repair. I've found they cause problems like yours more than any other reason.

I personally don't think it's a carb jet plugged if you are able to pump and keep the engine running. However, those carbs are extremely easy to work on. The only word of caution I'd give is IF yours has the plastic top and bowl be very careful torquing down. Follow the torque sequence and tread lighly on torque values. They are very sensitive to stress cracks and can't be treated like the old all metal carbs. I recently went though this on a 1991 9.9hp OMC Sailmaster where the previous owner cracked both...and there are NO aftermarket parts for these, only original BRP (read high $$$).

I'm not a mech but have trouble shot and changed a lions share of old omc fuel pumps and diaphragms. Bad pump diaphragms can still pump but not have the power to keep up with demand...getting spurts in the carb only means the diaphragm isn't totally shot...and not having to pull fuel all the way from the tank (head pressure). Also, there is no such thing as visual inspection to see a marginal diaphragm...a totally shot one yes, but marginal no. It can look good but be porous enough to give the symptoms you have. Just change the diaphragm anyway, especially if it's 10 yrs old.

Before you start pulling parts off the engine check the connectors and where the hose is connected to them. On old hoses the rubber gets hard, shrinks a little and the connection gets loose. The factory clamp band doesn't compensate for it. The easiest way to check is try to spin the hose on the connector while holding the connector stationary. If loose enough to turn easily it's either leaking air or on the verge of it...and could be your problem. To fix it, pry off the hose band and put a real hose clamp on. Don't forget to check at the primer bulb too.

The next part to check is the o-ring in the connectors. Sometimes a visual on them will show a split but they usually just get sloppy and don't seal tight anymore. The only way I know to be sure on the ones that look good is to put a new o-ring in or buy a new connector. O-rings don't last long like they used to and I see 2-4 yrs max with aftermaket versions. I've even had them go bad in a yr. Aftermarkets just don't last like the factory ones that originally came with your motor. I used to buy connectors every couple of yrs until learning how easy o-ring changes are.

That's it for now. Good luck. Those are great motors.

bp