Logo
FULL SITE MENU

omc 5.8 efi runs great in neutral but no power & seems to miss when accelerate in gear

A

albie

New member
I have a 1993 fourwinns 210 horizon, owned boat since new, has omc 5.8liter efi engine, 450 hours total usr, up until 5 years ago used boat alot but the past 5 years only use it for ten days each year, problem is boat seems to miss, has no power, & if get planed out top rpm is only 3100rpm, in neutral boat seems to run fine, upto 4600 rpm, i have done the following already, cleaned gas tank, checked vent,changed filter,checked fuel pumps, replaced distributor cap& rotor, replaced sparkplugs, unhookedoil pressureswitch but no change, hooked up code reader &system passes, my amp gauge reads 13 volts when engine running with no accessories orblower on, if turn blower on while engine running amp gauge drops below 13, is ther a voltage problem or possible fuel injector problem or maybe corrosion inside thedistributor, the cap& rotor were corroded bad but never looked any deeper at distributoro
 
Head over to sears and get a Fuel pressure gauge. My guess is you have a vst on the back side of the engine. The inlet screen on the pump gets full of debris. Is the electric pump whining loud when you turn the key to the "ON" position?
 
Fuel pumps dont & have never made high pitched sounds (starved for fuel) can tell pumps build pressure when turn key on, spin on filter changed, is ther any other fuel filter or screen or screens anywhere in fuel system that i shud check? Thanks
 
Had boat in water last 7 days, pulled out new plugs & chkd to see if any of them had not been firing & one plug was wet & could tell had not bn firing compared to all rest plugs, then with just me onboard it topped out at almost 3800-3900 rpm but when add 3 *****s it bogs down tryng to plane out , once do get planed out it seems to run fine at just under 3/4 throttle or 3100-3200 rpm, if open throttle more than 3/4 it mite gain 200rpm at best but can tell it is missing, i dont believe it is a fuel problem due to the fact that after running it at 3000-3200 rpm for 20-30mins & then idle it dwn it seems to run smooth but emits fuel vapors & smoke like its loading up on fuel
 
Also when had sparkplugs out i regapped them from..044 dwn to .035, that made it run little better which is leading me to believe the problem is that im not getting a hot enuff spark from coil
 
Profile??Salt or fresh?
You have a wet plug,then the manifold/risers gone bad or the head gaskets bad.Loosing 1 cylinder will make it run like crap.
Remove the manifold/riser and do a flow test/inspection.

93 it's about time for new manifolds.
 
Thanks, could u please explain further, whats causing the "wet plug" & what u mean by doing a flow test/inspection after removing manifold
 
Look at the end of the manifold for corrosion/blockage.
Hook up a water hose to the end of the manifold.It should allow as much water out as it lets in.
Any water in the manifold when you take it off?
Wet plug.The manifold/riser leaking back thru the exhaust valves.
Or a leaky head gasket.
Do a compression test.Post the results.
 
Thankyou, planning on doing another compression test over next weekend & will post results will also inspect & test riser, thanks again
 
Ok you posted " only 13 volts when running "

Verify that in fact you have only 13 volts the boat gauge may be off.

You should have over 14 volts.

You have a fuel cooler ? If yes should have a valve on it to bleed it.
 
Back
Top