Re: OMC Guru's---Dhadley, Walleyehead, anyone....
Are you having an idle problem? Read this segment about compression checking on outboard engines. Pay particular attention to the highlighted sentences. We have already determined that he can reach 5500 rpms by squeezing the primer bulb and tilting the motor.<br />I personally dont think blowby is the culprit. I standfast its a fuel related/ combination of things problem.<br />__________________________________________________________________________________________________<br /><br />Compression is the heart of an outboard. If one or more cylinders are damaged due to improper timing settings, lean fuel condition, overheating, or stuck rings from carbon buildup, your outboard is about to become history. Does a compression test alone always determine that my outboard is in good shape? Suprisingly the answer is "no". A good compression reading does not completely determine internal conditions. To correctly diagnose condition of pistons, rings, and cylinders, a leakdown test should also be performed. Using a quality leakdown tester, each cylinder should not show more than 10% loss. If any do, there is certain to be an internal problem in the making. For example, a compression reading of 120 lbs would be viewed upon as a good cylinder by the average person. This may or may not be the case. If a leakdown test of the same cylinder indicates say...20% to 25% or more leakage, it would be a good bet that excessive wear, scored cylinder, the cylinder scratched, and/or the rings stuck or damaged in a way that does not show up with a simple compression check. In any case, wear or damage is present and advisedly requires attention before further damage and/or exceptionally poor performance and efficiency results. Most common effects from diagnosis of excessive leakdown would be in the idle range of the motor. If all other motor functions check out attempting to diagnose an idle problem, then its a good chance that blowby is the culprit. It is advised that leakdown tests should be performed at the beginning of the compression stroke (rings just above exhaust port opening, which is the critical point), and NOT at TDC. Make sure you have flywheel locked down securely when doing a leakdown test. If you try to hold the motor from turning with a socket and breaker bar, you are putting yourself in a dangerous position should the breaker bar slip from your hand. Purchase a compression gauge and leakdown tester to go in your boat's toolbox and check cylinders a couple of times a year to ensure there is nothing unusual going on internally. Using proper grade of gasoline and outboard oil is essential to preventing internal problems. Proper winterization procedures will also do wonders to prolong the life of the internals of your outboard. If compression check shows more than 15 lbs difference on any given cylinder from highest reading of other cylinder/s, or if leakdown test shows excessive loss, you have a problem in the making! DO NOT continue running the motor until problem is diagnosed and repaired! It could result in causing much more internal damage than you already have.
<br /><br />Dhadley, what do you think of tysidor's fuel symptoms?