Maxum 24 5.0L Engine starting problem

[lane2]

Hi this is my first post as I am a new member and the 2000(yr) Maxum 24
is new to me. I moved from sailing to power boating.
I just rebuilt the trim pump and
I believe it is working ok. DN works ok, Trailer UP works, but the UP sw only moves a few inches. not main problem. The engine wants to start and will run with the key held in start position. When I let go of the key the engine stops. Boat is still on trailer. When key is turned to first position the alarm is on this could be normal? In the start position the solenoid engages and all is normal until I let go of switch. Any ideas? Where is the slave solenoid located and also the circuit breaker. There is a solenoid attached and I think it is
part of starter motor.

[mmwjr]

Welcome aboard

Trim up works but only a little bit, sounds like the trim limit sendors is not adjusted correctly.

Never hold the key in the start position with the engine running as this will damage the starter.

2000 should have an electric fuel pump which gets power from the starter when cranking then an oil pressure switch once running. I bet the OP switch is bad, common issue.

Under Documents of this site is the mercruiser manual for your engine.

Engine breaker (red button) is on top of you engine and the slave soleniod is next to it, these have nothing to do with the issue you described.

[lane2]

Thanks If the trim limit senders are on the right and left side of the out drive, I have an exposed black wire on the right side. Hard to get to for repair.

OP means?

[lane2]

Ok, I know op is oil pressure sw.

[lane2]

Are you saying that if the OP sw is bad and is replaced that the engine should keep running after I quickly release the start key?

[mmwjr]

Originally Posted by lane2

Thanks If the trim limit senders are on the right and left side of the out drive, I have an exposed black wire on the right side. Hard to get to for repair.

OP means?

If the wire is exposed or broken they need to be replaced and it only makes sense to do so when the bellows needs replacing.

[mmwjr]

Originally Posted by lane2

Ok, I know op is oil pressure sw.

Yep.

[mmwjr]

Originally Posted by lane2

Are you saying that if the OP sw is bad and is replaced that the engine should keep running after I quickly release the start key?

Correct if that's the problem which I believe it is but to test you can install jumper between the lead to verify. The switch is a safety feature required by the coast guard, if the engine stalls the switch open from lack of oil pressure and removes power from the fuel pump to prevent flooding the carb which can be an
Explosive issue.

[mmwjr]

Here's the wiring diagram for the fuel pump, 6 is the oil pressure switch which is mounted on the port side of the engine block just above where the oil filter is on the block. if you have a remote filter it's where the remote adapter is on the block.

[lane2]

Thanks for the help. I will replace soon.

Lane

[lane2]

Thanks for the help. I will replace soon.

Lane

[shrew]

Welcome aboard Lane2!!!

Moved thread from "Forum Support | Suggestion Box | News" to "Engines"

[Ian E]

Welcome! Good luck getting it sorted.

[lane2]

I talked with a boat engine mechanic and learned that if the kill switch is off the engine will not crank. Well in my case on my Maxum 2400 scr 5.0 L engine it did turn over. Bottom line I must admit my kill switch was off so when I let go of the key everything went dead. No problem with oil pressure switch as I jumped it for a test. I should have known, and now engine is running.

[shrew]

Kill switch will allow the starter to spin the flywheel. It will not allow the engine to start. So it will crank until the battery dies. Misleading information provided by the mechanic.

[mmwjr]

Originally Posted by shrew

Kill switch will allow the starter to spin the flywheel. It will not allow the engine to start. So it will crank until the battery dies. Misleading information provided by the mechanic.

Correct, kill switch opens power to the ignition, cranking circuit still functions.