Re: 86 90hp Merc will not run over 2k rpm's
Welcome to iboats. I think every outboard question known to man has been asked here. The beauty of this site,is in it's management. They've allowed a seamingly endless amount of space for pages upon pages of such questions to accumulate, to the great benifit of those who come around at a later date with the same ailment.<br />Get a cup of coffee, sit down, and click on "SEARCH", and type the ailment into the subject field, and read until it puts you to sleep.<br />Don't feel bad about asking any question here.<br />It sounds like you have not wasted one minute or one dime so far, as you have addressed some things that could cause a drop in RPM, namely fuel starvation.<br />But having addressed those, there are other fuel-related problems that can cause those symptioms, but not limitted to fuel.<br />Let's take it step-by-step, which is
precisely the way a marine tech would attack this problem;<br />1. compression test. Buy or borrow a compression gauge. They're pretty cheap, starting at around 15buks for a reliable one on up. But most good auto shops will lend or rent diagostic and specialty tools.<br /><br />2. While you're there, buy a spark plug tester, or ;<br /><br />one alligator clip, some spark plug wire( 2 feet should be plenty), and a 1/2" to 1" hose clamp.....And make one.<br /><br />3. You need a shop manual. It will give you the values of all specs, wiring diagrams, cautions, and oddities particular to your motor, and all maintainance intervals. And they
allways pay for themselves, guarunteed.<br /><br />4.If compression and spark is good, go back to fuel system. <br />Check the tank for clogged pickup,<br /> the fuel line for air leak (must be air-tight,<br /> along with all fuel fittings),<br />Check tank vent,to make sure it is open,allowing tank to get air.<br />Check the primer bulb when acting-up, for collapsing, or lack of firm.<br />If mushy, squeeze it, and see if perfomance improves. If so, it's fuel pump or compression.<br /><br />Check plugs and norte thier condition, and which cylinder they came from. They can tell you the whole story usually.<br /><br />Check all electrical connections one-by one, by pulling. cleaning any corrossion off with a small wire brush, and re-connecting..But remember, one-at-a-time (don't want to get crossed-up).<br /><br />Again ,you are right on track so far. It may drive you nuts by the time you find it too. But i'm convinced this is why marine mechanics make such good money
<br /><br />Buncha crazy rich guys, stompin-around behind the dealership cussin and swearin and throwin things that go "clang" and "KLINK!!" lol<br /><br />Anyway, good luck,and let us know your progress. in this same thread.
