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Wide open throttle question

bobb

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" I own a 50hp. evinrude that

" I own a 50hp. evinrude that is experiencing a problem at wide open throttle. When the boat is running at wot, the engine will run fine then bog down severely. Then it will start to accelerate, then will bog down again, then accelerate and will run fine. This problem appears to happen only while running forward in gear, not in reverse or in nuetral while throttling. I've checked for water in the fuel and there appears to be none. The only obvious problem is the choke solenoid does not work. Any help would be appreciated. The year is 1994, 2 stroke. "
 
"Bob.... Surging is usually a

"Bob.... Surging is usually a slow type up and down scenario (fuel related) as compared to a quick sharp up and down scenario (ignition related). From what you've said, I assume that you're speaking of a slow type surge.

This is usually due to one of two things, either a air/fuel leak (which if it existed, you would no doubt smell or see it), or a fuel restriction. However a fuel restriction, once occurring, stays restricted..... but you state that after the second bogging the engine runs fine, which is somewhat confusing. That shouldn't happen.

At any rate, check the fuel primer ball to make sure that the valve closest to the engine hasn't come apart, having the inner portion of the valve fall out, turn around, then be pulled back into that valve housing backwards.

Also, to the left of this page there is a "Keyword Search" feature. Click on that and make a search using the words "anti Siphon" without the quotes of course. That will lead you to many articles I've written on that anti siphon valve, what it is, where it is, and what to do about it. Keep me informed.

Joe
"
 
" To better clarify the proble

" To better clarify the problem, after start up I will be running then all of the sudden the engine will bog down to idle speed. There will be surges, yet will remain at idle speed. If I shut down for 30 minutes and restart, the engine will run for about 5 to 10 minutes then experience the same problem. Is it possible only 1 cylinder is firing and any way to check this possibility will underway? Thanks. "
 
Use a timing light on the spa

Use a timing light on the sparkplugs and take it for a run . Alternate between cylinders when the engine acts up. This will help in de
termining fuel or spark problem.Lay the timing light on the seat and observe the flash.
 
check the fuel conection to t

check the fuel conection to the outboard sometimes the ruber tubing around it cracks or valve inside get's jamed with stuf. most of the time just geting a new one fixes the problem.
 
" Bobb,

I have no inpu


" Bobb,

I have no input for you on how to diagnose the problem, but if you have reason to suspect that one cylinder isn't firing: use a pair of pliers with a rubber insulated handle (prevents shock), when the engine is acting up, pull a spark plug wire off. If the engine continues to run the same way, you have found something; if it runs worse, you know that the plug is firing to some degree, stick the wire back on and try the next plug. If you try this be sure to use rubber insulated tools and pay close attention to the flyweel. It may even be a good idea to shut the engine down before you pull the plug.

Jon "
 
" Thanks for the input. I beli

" Thanks for the input. I believe I've found the problem. After checking for spark, I wiggled the spark plug wires and this seemed to have an effect (ran better). It is an intermittent problem which can make it frustrating. Thanks for all your advice. "
 
" Bobb,

Have you positively


" Bobb,

Have you positively identified the problem? Was that it? Like to know what your results were, I have two older outboards and want to be prepared when its my turn! "
 
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