73' evinrude 50hp bogs at wot, pulling my hair out

1st hey yall im new here, ive been reading posts on this site for about 3 years now and have always found my answers in other posts, yall have helped me alot. im fairly inexperienced at working on outboards but i do have better than average mechanics skills. heres what i got, and for the sake of saying so my manual has been ordered (should have done that along time ago) last year the "get up and go" of my motor seemed to be on a downhill slide, all winter and spring has got worse and worse. its an old motor that sat up for a long time but a good cleaning a few years ago and it was great .but now ive been through an aray of work.compression test- 110 top cyl and 120 on bottom cyl, ive replaced the impellar and rebuilt the whole water pump, carbs tore down, cleaned rebuilt, fuel pump rebuilt and still would not pump (vacuum from crank case is good) so i bypassed it and installed an electric pump, replaced every fuel and vacuum line, new spark plugs, new coils, new power pack, new starter sellunoid, good fresh fuel. when in the water in neutral its strong. as soon as i move to wot, it craps the bed.
does this sound like a link and sync issue, maybe timing advance. any insight would be greatly appreciated. thanx in advance, this is a kick-***** site

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

Don't have much time , search for the thread "Stalls when I put it in gear", and check if the stator is sticky to the touch or looks as if it has tar driping from it, and get a book on the thing.
Zeke

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

Sure sounds like dirty main jets to me, everything is fine and all checks out but it won't run.

They are in the bottom of the float bowl, if you don't have a manual they are easy to miss.

Pull the drain plug on the float bowl, they are inside there and you need a long skinny screw driver to get them out, then run a stranded copper wire through them.

Using a can of the computer air works pretty good to blow things out.

An easy way to check if ti is a fuel problem is to get it running and squirt a small amount of premix into the carb throat, if it takes off it is a gas issue.

Had similar issue awhile ago, got a bunch of new parts out of it btu never got it to run till I cleaned those jets, I have an '81 50.

Try that and post results.

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

those motors are very finicky. the timing has to be right on, the link n sinc perfect, and the carbs have to be clean, get rid of the electric fuel pump, extreme FIRE HAZARD.

this works very well on those motors, http://forums.iboats.com/showthread.php?t=228183

http://forums.iboats.com/showthread.php?t=244013

linc n sinc is under synchronization in your new manual.

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

Sounds like junk in one of the high speed orifices to me. As stated, if you don't know they are there, this is an easy item to miss.

I also agree that the electric fuel pump is a bad idea. The fact that it hasn't helped also tells me that it isn't needed. I am curious as to why you think the stock fuel pump wasn't working, however.

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

A poor O-ring seal in the fuel line connector would allow the manual fuel pump to suck air.

Installing an electric pump before the motor may hide this, but as everyone say, this is NOT a good idea.

Test your manual pumps output by temporarily installing a clear hose between the fuel pump and carb, watch for any air bubbles, indicating air sucking into the system.

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

thanx for the resonses, to answer a couple of things. i determined that the fuel pump was not working by simply pulling the output hose the the carbs and cranking the motor, nothing came out. i do tend to use old mechanics tricks as im working outside and thats just what i know. o-rings on connector, i have removed the quick connector on the engine and run an entire new fuel line from the tank to the carbs leaving the only quick connector at the tank because i have 2 tanks
as far as the electric pump im just curious, not trying to argue at all, just getting info. im a little confused on it being a fire hazzard because it is a fully sealed unit and in that compartment with batteries and many other electrical connection, its probably the least likely thing to crate a spark. is there something i dont know about here? electric fuel pumps get used so standard these days on all kinds of engines because they are more efficient, fuel flow is far more precise and consistent which in theory should provide a much more stable run. again is there something im missing here
CARBS, are the high speed jets in the float bowl behind the "plug" screw? i have cleaned them by spraying carb cleaner and air through them, chemicals "appear" to pass right through. i have not actually removed them. i am fully willing to do so, ive had these carbs apart so many times it seems like i could rebuild them in my sleep, again unless im missisng something.
like i said in my original post, i ordered the manual yeterday and wont have it for a couple days, just trying to do everything i can till it gets here
for curiosity sake and i know i need the manual for this, could some one describe to me what a "linc and sync" is
last one, very stupid question, im doubting that this has anything to do with it but just for the sake of covering everything i can. is cylinder #1 on this engine the top cylinder? i beleive someone told me once that it was but i could have just imagined it. when top cyl is at tdc the zero marking on the flywheel lines up with the timimg marker, just checking that its lined up with the right cyl.
again thanx for all the help

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

The O ring they are refering to is on the base of the fuel pump, it plugs into the block and operates off the intake pulses of the engine, if that O ring is bad it will break the vacuum and cause the pump to not work.

The jets you want are behind that hex screw on the bottom and no, carb cleaner and blowing them out won't get them clean, they need to be removed with a long skinny screw driver and have a wire run through them.

Mine looked clean as the day they were installed but the motor wouldn't run, ran the wire through them and it ran like a champ.

On an outboard the timing and throttle are linked, if one is off even a little the engine won't run right, you get too much advance and no gas or vice versa, once you clean the jet and do the sync I think you will be really suoprised how well it runs.

Yes the top cylinder is #1 and the one you want to set timing.

Re: 73' evinrude 50hp bogs at wot, pulling my hair out

thanx for the help, ill do those and post my results