Won't Crank...Help

[jwfoster4]

This boat has never failed to crank; until now.

Here's the deal. Turn key to "on" and don't get the familiar low oil pressure alarm sound. That's got me curious, but don't really know where to start tracing it.

I try to crank and engine turns over fine but won't fire. All fluid levels are fine and gas is fresh.

Any ideas?

Thanks

 

[David Morgan]

Its either fuel, spark or compression. Start with the simple things first. Pull a spark plug wire and put the ground against the block and crank. Do you get a spark?

Do you smell any gas when pumping the carburetor?

Without the low oil pressure indicator, I suspect its electrical.


Refer to the trouble shooting section of your engine manual.

 

[Cocktail Time]

Do you have a kill switch with a lanyard? I think that is the right word. I have helped a dockmate with a bad kill switch whose motor would turn over but not fire up, almost as if it were out of fuel. He had twins so we used the kill switch wiring for the motor that would run and when we swapped the kill switch she fired right up. Hope that helps...

 

[BonBini]

From your description (cranks, no start, no oil presure alarm): I too believe you are not powering up the igition (run circuit). As previously mentioned, look at some switch positions and fused circuits. If you have to start digging into it deeper, I would start at the ign switch. A wiring schematic would certainly help too. These little problems are good for getting to know you boat. ... Ron

 

[tobnpr]

I have no clue how your boat's wired, but typically the gauges are wired to the ignition circuit as well. Do the gauges function with the key in the "run" position?

 

[Asureyez]

From experience there are so many things that cann go you you can't expect a "do this solution." we have to make you work for it!

Here is what I do. I recall the last know state when every thing worked fine, and ask. What has happened since. Nothing? No repairs, no one else on the boat etc. I then start with the obvious, Batteries, Check the voltage at rest, turn off Battery mains and check volts YOu need 12.8+ low, charge batteries without drains start. No?

Check voltage at starters, hot at 12.8 then start, no Low volts?, trace lines and clean all connections uncluding battery lugs and emergency start solenoid. Re check battery volts and volts at starter. Got volts -start, no?

Trace to fuel shut offs, connections and volts. clean contacts, If your Batteies are hot and you have volts to starter and fuel solenoids, and you crank but don't start, go to ignition and troubleshoot, check for condensation shorts etc. Do you get fuel vapor in exhaust? No fuel vapor but cranks and you have spark, clogged filters, water in fuel etc.

Good fuel, losts of spark, clean air, cranks but won't fire up ... Trace wire harnesses from ignition switches, they are buried make sure the block connectios are super tight and the wire tie tight. Start, No, get a hammer and kill broker that sold you the boat.

 

[Liquid Pleasure II]

Just went through this on my boat. Turned out previous owner put Wal-Mart spark plugs in, not Mercruiser recommended plugs.

Changed plugs then it fired right up. Then the other engine went our 2 days later, same thing.

I know, I know sould of changed both at the same time but sevice only had 1 full set.

Good luck!

 

[Luckydogs]

Both of mine did the same thing last summer, turned out to be the ignition sensors, easy fix.

 

[lucknow]

From your description (cranks, no start, no oil presure alarm): I too believe you are not powering up the igition (run circuit). As previously mentioned, look at some switch positions and fused circuits. If you have to start digging into it deeper, I would start at the ign switch. A wiring schematic would certainly help too. These little problems are good for getting to know you boat. ... Ron

I agree, start here.
This past summer I diagnosed a similar no start problem with my nephews 270 Dancer, the wiring connetor under the throttle controlls was corroded causing power loss to engine circuits. FYI, this connector was not shown in Sea Rays wiring schematic we had for his boat, we found it by following power along harness from ignition towards engine.

Compare power readings between connection at engine harness and ignition switch, you will most likely find one circuit that has power at ignition switch and not making it to the engine harness.
Good luck
Keep us posted with your success!!
Kevin

 

[jwfoster4]

It was the "dummy" switch at the end of the bright RED lanyard. Guess who's the dummy. It was just slightly down, just enough to not let it crank. :smt021 The one on the left is me. Put it in the right position and it cranked right up.