multi species angler
My recently purchased 25hp mariner seems to run great, but when held wide open it cuts in and out. It is a 1983 built by Yamaha. Anybody have any suggestions as to what the problem might be? Thanks
Sounds like your getting close...as freyed suggested, the spark may be weak. First make sure the gap in the plugs is correct. Before changing the coil, switch the location of the spark plugs and try it again...just in case you got a bad plug (even new ones fail sometimes). If the result is the same, then check the plug wire cap...sometimes they can loosen and not make good contact, reducing the current to the plug. Then pull both plugs, insert them into the respective plug wire and lay them across the cylinder head so they are grounded. While watching the spark plug, give the starter a yank and see what kind of spark you have...should be a solid blue spark and both should be the same...if the coil is bad on one of them, the spark will be a small yellow spark (or no spark) rather than a bold blue spark. I hope this helps you further trace to the source of the problem...isn't it funOk this is where I am at right now.
While running I can take a plug wire off and it stills run just a little rougher. I put that wire back on and take the other off and it stalls. Is this a clue to any problem.
On a side note, I was wondering if anyone knows if there is an adjustment to make the throttle stick in any position? The only way to keep trolling speed now is to continuously hold it in position. If I let it go it goes back to idle speed. My 9.9 would hold open in any position.