at a loss on a 97 50hp Evin

[saltfly]

Ok I’m at a lose. My friend brought his 97 50 hp evinrude back down. It just wasn’t getting full throttle. When I got it running in the spring, it started and run on the hose fine. Except for a miss I couldn’t figure out. The power problem was my fault. He told me it run great, till he stored it for  a few years and then it wouldn’t start once he went to use it. To make a long story short, it end up being the power pack. So I replaced it. I assumed that all the linkages where set right since he said it run fine. Which I know better, assumption is the mother of all screw ups. So I should have check everything. Once he got it here, I took a really good look this time. All the linkages where all screwed up . So I reset, everything back to the factory spec’s. It now gets full throttle. It runs good, all except that miss and now its bugging the hell out of me. I rechecked the whole electrical system and its to spec. I feel it’s the timing, but my timing light is getting old and I’m not sure I can trust it. But when I use it to check the timing, it s off. My book tells me it should be 18 to 20 degrees BTDC at wide open throttle. I’m reading 15 degrees. The miss is through out the whole throttle range. But the dam thing starts so easy. So does any of you motor guys have any ideas? All yea this is how I check timing. A old outboard mechanic showed me this years ago. Unhook the harness, then push the throttle all the way forward. Then take out the plugs. Hook up the timing light and a remote starter switch. When you crank the motor, it turns over fast enough to read the timing. Of course you need to be in the shad. I check this with OMC, when they were in biss. And was told that will work with a good timing light. But they don’t recommend it , because to many people don’t use really good lights. They also said a lot of shops use that method. So what do you think?

[dburr]

Walt, what you know is that she is running ruff for you.. You have found a bunch of stuff wrong that you have corrected and have made good progress.. I think that you've already answered your question and just need trust your instinct!

Don't stop now! Put the timing where it is supposed to be and that will help smooth things out and also help give a little more power.. If you have a late spark at higher speeds you will not get a good burn so you will be waisting gas.  With late timing, she will still start so don't let that be a distracter..

Good luck!

[saltfly]

Thanks for the reply Dav. Yea my gut keeps saying timing. But my old light may be going bad. Sooooo today I'm heading out to get a new one. Why I think it is timing. As the rpms go up the miss, is consistent with the rpm's. It speeds up and slow down with the rpm's. To me this says timing, but I've seen some crazy things with out boards and thought It would be best to check with others. Just to make sure.

[dburr]

Thanks for the reply Dav. Yea my gut keeps saying timing. But my old light may be going bad. Sooooo today I'm heading out to get a new one. Why I think it is timing. As the rpms go up the miss, is consistent with the rpm's. It speeds up and slow down with the rpm's. To me this says timing, but I've seen some crazy things with out boards and thought It would be best to check with others. Just to make sure.

Crazy things, you ain't kidding.. Just wait, it's gonna be because the E is faded on the cowling and the wheel nut has the cotter pin in backwards!!    

[fitz73222]

Look for a cracked coil lamination or plug wire trying to ground to the block. This might explain a miss that is timed with the RPM change. Run the engine at night and see if the coil or wire is doing the arc dance.

[saltfly]

Thanks fitz I’ll take the coil pack off and take a look for cracks, I replaced the plug wires with new ones, but that doesn’t mean they are good. I’ll run it tonight to look for spark jumping to ground.

[Dhadley]

Assuming the fuel is fresh and the carbs are clean make sure you have Champion plugs in it. With todays fuel the QL77JC4 plugs are a good choice.

[Georgie]

Not sure if you're past the timing part of your diagnostic session, but excess feedback can't hurt.

If you are reading 15 degrees in the yard and the manual recomments 18-20 degrees, then your timing is correct!  It should not read the recommended advance degrees unless you're timing it in the water at speed.  Approximately 4 degrees lower is the correct reading when testing in the yard and turning the engine over on battery power.

Here's an excellent link on timing OMC cab'd engines:
http://forums.iboats.com/engine-frequently-asked-questions-faq/joe-reeves-wot-timing-procedure-228183.html

[saltfly]

Thanks   georgie that’s the method I use. So its good to know it’s good to see other are doing the same. I didn’t know you should be 4 degrees  lower though. That means my timing light still works. But for right now we are giving up on that motor till the fall. It has become a sore spot for me. it’s the first Evinrude or Johnson that I have not been able to solve problems on. That gets to me a little. Makes me feel I’m letting my friend down.  This fall I’m taking everything off of the motor and cleaning every connection and part. Then reinstall everything. Nothing will be left out. It sat for 4 years, so I'm sure that had something to do with it. Something is braking down under a load. I just have to get my rib cage back into shape so I can run it on the water myself.

[Georgie]

Totally just wasted a long winded response b/c I forgot to copy it or write it in Word first.   :evil:

Here's the short short version.    Not only does your timing light work, but it shows that the current setting is accurate!  

Now for the fun stuff...

Have you checked for possible intermittent arcing/grounding of your spark to the block after dark as Farley suggested?  It's a REAL good and easy way to check for an obvious electrical fault.  

That said, I imagine you've checked the basic carb and fuel related possibilities?  For simple clarification's sake, timing is merely synchronizing a certain position of the crank to the static charges generated by the stator/timer base under the flywheel.  Do you own or have access to a factory service manual for this engine?  I ask b/c each component of the ignition system can be verified with a meter to see if it matches factory resistance and/or continuity specs.  

I hate to see you give up early but I understand the frustration.  My ol' girl currently has me pulling out my hair b/c she's developed a tapping/knocking noise and is misfiring/wobbling at idle.   A few hours of diagnostics later and I'm still at a loss  :(   Try testing the electrical to spec before you give up entirely.  It'll only take a couple hours and you can feel like you've exhausted all options afterward.  You may find a coil, stator, or powerpack that's just not carrying or producing the charge it's supposed to.  
Good luck!  

[saltfly]

I’m giving it up right now, because its over 100 miles away. So He wants to use the boat. So it won’t be available till fall. Soooo that will give me time to think about it and heal. Once it comes back, I’ll take it out and run it. My friend says at full throttle it feels, as though it wants to go but just won’t. Until I get it on the water myself. I won’t know what he really means. On the hose and in a barrel. It runs great. So this problem is a load problem. But again, till I get it out myself, I can’t really know what he means. Oh well, it’s one of those things that will bug me till I solve the problem. Some times when you think you have something under control. Something will jump up and humble you. This motor has done that to me. :cry: