1973 18 hp evinrude Driver Coil test

[oldboat1]

^^agree. On the needle setting, I would tweak it clockwise 1/8 turn at a time, waiting briefly for the engine to respond. Repeat until the engine stalls or lean sneezes, then back the needle out about 1/4 turn. Should be about right.

Sounds pretty close. Might be time for a fuel pump rebuild or replacement (couple of cheap ones, maybe).

 

[KC9000]

@racerone , with cowling off it was similar, here is a video where I take it off, you can see the exhaust here as well, it was blowing away towards the garage. I do not have a fan blowing exhaust away, I did a decarb on it. The spot I was tho on that wall its like a wind catch, so wind was going upward, in this video you can see the exhaust, also when I take the cowling off it dies shortly after, and again at the end of the video. @oldboat1 , I might just do a new fuel pump, might as well right...is there a big difference between the 0388684 that Is for my motor or would a 0388685 work? One is more expensive then the other. Also how would I know its a bad fuel pump, I did take it apart and check Diaphram and did the blow test on it. Both checked out.

 

[oldboat1]

Lift the tank up at the powerhead height when it wants to stall. Weak pump will probably show improvement. Some of the square pumps are deeper than others, which may make a difference. Check the one that is on the motor (If a new one sticks out too far, the hood might not fit over the top).

Diaphragms can be holed/torn. But if old, the diaphragm can also take on a set -- texture of leather. In the former case, the pump generally fails. In the latter case, the pump just doesn't push gas as well. New diaphragms are completely flexible.

 

[KC9000]

And I'm sure rebuild kit is cheaper then new pump, do you think rebuild would be sufficient?

 

[KC9000]

Would this fix a qeak pump? Or would I need to get a new pump?

 

[ct1762@gmail.com]

i've had decent luck with those cheapo aftermarket pumps... just be careful not to over-torque the mounting screws as they will leak. but a rebuild kit is fine, too. just takes more labor as the new replacement pump is same price or cheaper.

 

[KC9000]

Valid point there.... decisions...lol

 

[KC9000]

Like one of these, if its clearance issue, I can just swap the base of the current one of the engine.

 

[racerone]

About the only thing that can go wrong with the fuel pump is the diaphragm $6.00 or so and dirt on the check valves .----Easy inspection and fix.----Otherwise you are not learning by " trying " another pump !

 

[KC9000]

Yeah I was thinking about the rebuild kit over the new one, I took this one apart once already and inspected the Diaphram and check valves and they looked like they were in good shape, buy never hurts to throw a 6 dollar Diaphram in just to be sure. I love the advice!!

 

[oldboat1]

Hey KC -- Did you try raising the tank to the level of the powerhead or above? I have no documentation to show that's a valid fuel pump test, but seems to have been determinative for me on a couple of occasions. If the pump is too weak to lift fuel from ground level, believe it would likewise struggle to raise fuel from the floor of the boat.

 

[KC9000]

Not yet, I will try that today after work. Before dismantling the fuel pump.

 

[racerone]

Factory kit comes with instructions .---Guaranteed not to be " chinesium " parts.---Fix it right the first time.-----And really the diaphragm is the only thing that fails !!!----Available $4.54 as a part by itself.

 

[racerone]

The diaphragm may not be listed for your 1973 model.----But there is a list as long as your arm (200 models or so ) of motors that use the pump and that same diaphragm.

 

[racerone]

That pump was first used in 1968.----Used as late as 2007 as well as a modified version and as a vapor extraction pump on the V-4 and V-6 model up to 175 HP

 

[KC9000]

Raised the tank to level and it did not change the operation of the motor, ran the needle back til it started to cough and ran it out til it quit coughing and she idled a little better, but still had a slight shake. I will be taking her fishing this weekend. Iran the motor for several minutes before lowering the tank, I started the video late, but put the tank on the ground and it was exactly the same as elevated.