Q & A — November 2002
By Capt. Ken Kreisler
| Part 2: Fuel-Bleed System, and more
got a 90-hp two-stroke outboard that I am told might have a problem with
its fuel-bleed recirculation system. Can you explain how this works and
what can happen if it fails? B.A., via e-mail
Many recirculation systems also collect the fuel and oil pooled in the lower crankcase bearing area and pump it to the upper crankcase bearing to ensure proper lubrication in this location. If this type of system fails, the engine can suffer an upper crankcase bearing failure. Regardless of the type of system, excessive fuel and oil will puddle in the crankcase and not reach the combustion chamber during low-speed operation, causing a lean mixture. When the engine accelerates, the puddles will be quickly drawn into the engine, causing a temporary rich mixture that will result in poor low-speed performance, poor acceleration, spark plug fouling, stalling or spitting at idle, and excessive smoke on acceleration.
is the difference between intercooling and aftercooling? S.C.,
help with a maintenance problem? Write to Maintenance Q & A, Power
& Motoryacht, 260 Madison Ave., 8th Fl., New York, NY 10016. Fax:
(917) 256-2282. e-mail:firstname.lastname@example.org.
No phone calls, please.
This article originally appeared in the October 2002 issue of Power & Motoryacht magazine.