1990 454 mag lost power
 

Trying to winterize my boat and I lost power during idle. I am pretty low on gas but plenty for idling. Maybe the fuel filter is plugged up or the fuel pump is shot? I’m not sure, not mechanically incline. I need some troubleshooting advice. The boat turns over, the battery was low but I have it on charge right now to try again when I troubleshoot tomorrow. It ran for 15mins, I switched over to the antifreeze but it died after running for a minute and wouldn't start back up. So, what should I try?

If you dribble some fuel or spray some carb cleaner or…..does it start for a second than die?

if no,

when you hook up your $15 spark tester found in all auto part stores, does it show spark ?


https://cimg0.ibsrv.net/gimg/www.off...b97719e16a.jpg

Also, using your multimeter what voltage does your battery have ?

I didn’t have a ton of battery life m to troubleshoot but I did spray some starter fluid and nothing happened. I’ll get a spark plug tester tomorrow. It’s just weird how it died after running for like 15mins. I was thinking it was maybe something sucked up into the fuel filter, is that right below the fuel pump? Or the fuel pump itself.

There’s a cannister one, in frt if engine looks like an oil filter, and a small one in inlet of carburetor.

if you sprayed ether in carb and not even s mutter, than probably spark.

We never get a warning when something is going to go bad.

Is your ignition a Thunderbolt iV ?
Do you have a lanyard ?

No idea about the ignition, too dark to check now. Like a kill switch lanyard? I flicked that on and off just in case. Spark plugs are new, thinking the distributor?

omg. Lol. :wink I’m asking questions/making statements so i can gather info and help you with how to diagnose your issue.

All you need for now is flammable spray liquid :) , volt meter (cheap is fine), spark tester, memory of maintenance done and when, and be able to answer ir find answer to some questions. It’s the only way without being their to disgnose ourselves. :thumbs

Starting fluid can be pretty aggressive on engines. Though it's worse on higher compressions.I prefer to use gas in an easy to apply method into the carb intake.

Like the breather end of 1 gal jerry can. Easy to direct into the carb, without spills, and easy to meter.

But you should be able to see the carb discharge fuel when you move the throttle...if there's fuel in the bowl.
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If no fuel...is it a mechanical or electric pump? Have you got a fuel pressure guage?

if you've got fuel in the carb, and it's not firing, then check for spark...as suggested.

The ignition components can die instantly, and at the worst times.

Could be the module in the distributor

hit the throttle, it’s delivering gas…. So it’s electrical. The battery is fine, engine is turning over strong but there’s no spark.

Guessing my next move to replace the distributor and rotor?

Look like the one I should buy?:

A.A Tune-Up Kit Distributor Cap Rotor for MerCruiser GM V8 Thunderbolt IV, V, HEI Ignition System 18-5273, 805759Q3 https://a.co/d/iQcMcER