'72 johnson 50hp problem with timing?

[jbjennings]

I've gotten my 50hp running but can't seem to get it right. It will idle and run, but not smoothly. It seems like the timing is bad at all throttle positions. It has a terrible miss at all speeds. It will not open up wide open properly. There is a little fuel coming out of a hole in the back of the fuel pump, which I am planning on rebuilding if it's possible. I can't seem to find a rebuild kit for it. Pumping the primer bulb has no effect on running with throttle applied, although on idle it does seem to run out of fuel, so I know I have fuel pump problems. The fuel pump is not mounted to the block, but has a hose running off of intake manifold pulse, with the pump mounted onto the carb silencer.
I've put a new key in the crankshaft upon rebuild, along with new piston rings, gaskets, good pistons (used), and compression is about 150 on both cylinders.
I do have a crack in one or both of the coils, but my spark tester shows great spark on both cylinders (jumping a 1/4" gap with NO problem and super hot blue spark). I'm wondering if a coil could be causing this problem and if I should invest in new ones in spite of the good spark test.
THis motor has me wondering, and I'd appreciate any ideas on it.
Thanks,
JBJennings

 

[boobie]

Re: '72 johnson 50hp problem with timing?

Does it sound like an ignition miss or fuel bog?

 

[jbjennings]

Re: '72 johnson 50hp problem with timing?

Sounds like an ignition miss. On idle it has a bad miss and therefore a LOT of vibration. Definitely something wrong. I'm going to take off the flywheel and see if the key is broken or otherwise causing problems.
I did take apart the fuel pump and it was a goner. One of the metal reeds inside was corroded apart. I also suspect some of the crud from it went into my carb. Will rebuild carbs and try to locate a suitable fuel pump replacement.
I just don't think it's my flywheel key and have never seen a coil do something like this.
Thanks,
JBJ

 

[boobie]

Re: '72 johnson 50hp problem with timing?

Try putting a timing light on each cyl when it acts up. Look into the timing light and if you see black spots that will tell you which cyl is acting up. Also, will the ignition jump a 7/16" open air gap when cranking??

 

[jtexas]

Re: '72 johnson 50hp problem with timing?

Try shop.evinrude.com or ishopmarine.com for a replacement pump, or you can use the fuel pump from most any 70's or 80's 2-cylinder (non-vro). 3- & 4-cyl pumps have a larger outlet nipple, but would work if you can improvise an adapter.

Did you torque the flywheel to spec?

New plugs & wires?

 

[jbjennings]

Re: '72 johnson 50hp problem with timing?

Problem solved......
I took off the flywheel today and discovered the key was sheared and the motor was horribly out of time. I don't even know how it ran.
I will put a new flywheel on the bad boy, and find a socket at a pawn shop large enough to fit on that horrendously large flywheel nut so I an torque it properly. I can't believe some numbskull snuck out there when I wasn't looking and put the flywheel on there without a torque wrench. ...yes, it was me.
Let it be a warning to others not to pull such stupidity.
Now to find a fuel pump for the rascal----cheap. I found one on ebay for about $50 NOS. I think I may spring for it.
THanks for the help,
JBJ

 

[eavega]

Re: '72 johnson 50hp problem with timing?

Just for your reference, the flywheel nut on that motor (if its the same as the '72 50 HP Evinrude I had) is 1-3/8". If you have a Northern Tools nearby, they carry stuff that big.

-Rgds

 

[jbjennings]

Re: '72 johnson 50hp problem with timing?

Thanks Eavega,
BTW, I've been watching ebay for a while now and I totally lucked up on my crankshaft and starter and such. The prices they have on 50hp stuff now are outrageous. Even though I don't need it, I may buy a '72 with bad compression on one cylinder for $150 locally just for parts.
I appreciate your thoughtful offer a while ago on yours!
Sadly, we don't have a Northern Tool but I might try Harbor freight. I just don't need the big stuff that often---but when you need it, you NEED it.......
Later,
JBJ

 

[eavega]

Re: '72 johnson 50hp problem with timing?

I appreciate your thoughtful offer a while ago on yours!

Sold the entire thing to a local guy here about a week after we communicated. He got a great cache of parts for his 50 HP Evinrude plus a fully functional control. I got enough to mostly cover the cost of re-powering my boat with a '76 70 HP that my Yankee likes a lot more than the 50.

Sadly, we don't have a Northern Tool but I might try Harbor freight.

Harbor Freight didn't carry anything that big, that's why I went to Northern. The local Advance Auto Parts was willing to order one for me, but the price was a bit prohibitive for a one-time-use socket!

-E