1986 MerCruiser Trouble

[baker274]

Starts, runs well for 30-45 minutes. If I turn the engine off, it won't restart till it's sitting in the driveway 30 minutes later. Plenty of power, just won't kick over. Seems a bit hot, but temp gauge reads 175. MerCruiser 140 Alpha.

 

[Reel Poor]

Re: 1986 MerCruiser Trouble

it won't restart ----- Plenty of power, just won't kick over.

We need a better explanation. There is a difference between cranking and starting. Cranking is what the battery and starter achieve. Once cranking has been achieved (engine is spinning by starter power) the ignition and fuel system take over and the engine starts.

So, what is it doing, not cranking or not starting ?

 

[Bondo]

Re: 1986 MerCruiser Trouble

I'd Guess it's loosing either Fuel or Spark,..... Or it's Too Much Fuel,+ it's Flooding......

You're There,+ We're Not,............
You've got to figure out Which it IS......

 

[baker274]

Re: 1986 MerCruiser Trouble

The engine is cranking, but it just cranks and cranks and cranks. What confuses me most is that if it is Fuel or spark... why do I get a good 45 minutes out of it every time before it gives me trouble?

 

[kbetts]

Re: 1986 MerCruiser Trouble

Possibly a coil going bad, corision on the points or a bad condinser.

 

[DayCruiser]

Re: 1986 MerCruiser Trouble

When I had a similiar problem it was a bad choke. Star when it was cool and not start when it was hot--unless you pumped the throttle about 10 times

 

[mkast]

Re: 1986 MerCruiser Trouble

Classic bad ignition switch.

 

[baker274]

Re: 1986 MerCruiser Trouble

An ignition switch issue would show up while the engine was hot, vs. cool? How come?

 

[Don S]

Re: 1986 MerCruiser Trouble

I've worked on boats for a lot of years, and I wouldn't say it a "Classic bad ignition switch". If it was a bad switch, you would also notice the instruments not working as they are also on the ign. wire from the switch.
You may have a vapor lock/fuel problem or an ignition problem but until you identify which there is no answer.
You need to do two things when it won't start.
1. pull the flame arestor and see if fuel is being squirted into the engine from the accelerator pump when a helper pumps the throttle.
AND
2. See if you have spark, pull the coil wire out of the distributor cap, and hold it about 1/2" from a good clean ground and have your helper crank the engine. Should have nice bright blue spark.

 

[baker274]

Re: 1986 MerCruiser Trouble

Thanks for the advice.

No fuel being pumped means I need a new fuel pump.

No spark means I need a new coil... or a whole new distributor?

 

[Reel Poor]

Re: 1986 MerCruiser Trouble

Thanks for the advice.

No fuel being pumped means I need a new fuel pump.

No spark means I need a new coil... or a whole new distributor?

Neither of your responces are correct. Once you determine whats not present, then and only then can you attempt to diagnose which part has failed.

The fuel system contains more parts than just the fuel pump.

The ignition system contains more parts than just a coil and distributer.

 

[baker274]

Re: 1986 MerCruiser Trouble

Of course. Thank you.