How fast should a 5.0 merc engine start?

[donaldm]

I have a merc 5.0 i/o efi 2005 with 60 hours. Question to other with same. Anytime (hot or cold, full battery, week or months between) i start the motor it will crank for 3 full sec then fire up. Is that normal? Unlike my car which will start within a half to one seconds. Is 3 seconds the nature of boats by design?

 

[Don S]

Re: How fast should a 5.0 merc engine start?

They are slower starting than the automotive side. Probably due to the safety features built into them. Things like no spark till the ECM sees rpm high enough, and a reference signal from the distributor or other sensors.
When was the last time it had a full tuneup. Cap, rotor, sparkplugs, filter changes etc.

 

[donaldm]

Re: How fast should a 5.0 merc engine start?

its electronic fuel injection . . no rotor or cap. never change air filter its only got 60 hour run time. i did change fuel filter along with oil and oil filter. Sound like its a normal start time??

 

[Don S]

Re: How fast should a 5.0 merc engine start?

It's got a distributor, with a cap and a rotor, trust me.

 

[JustJason]

Re: How fast should a 5.0 merc engine start?

Boats tend to start slower because people never keep them in tune unless something breaks. Or they have voltage drops all over the starting system because of poor connections, bad cables, tired old starters that are drawing to much current because they are getting cranked for 15+ seconds at a time all the time because the engine is out of tune.
If all the maintenence is kept up with, and if you have no voltage drops in the starting system and your starter isn't tired and cranky, AND if you don't have a wimpy battery to start with... A boat motor should crank as fast, and start nearly as fast as a car engine.

 

[donaldm]

Re: How fast should a 5.0 merc engine start?

yes i guess it does have rotor and cap. I would think 60hours on an 2005 engine would be like new.

 

[Don S]

Re: How fast should a 5.0 merc engine start?

It's 4 years old, sitting around most of it's life doing absolutly nothing but corroding.

 

[Fun Times]

Re: How fast should a 5.0 merc engine start?

What is the cold cranking amps of your battery? It should be a minimum of 750 CCA, or 950 MCA, Marine Cranking Amps. Any thing less will take longer to start.

Also just for the heck of it you could try cycling the the IGN key on & off [without cranking the engine over] A few times to build up the fuel pressure before starting it And see if you get a better start time.

 

[Don S]

Re: How fast should a 5.0 merc engine start?

Good point about the battery boat teck, that battery should also be a starting battery, NOT a deep cycle battery. The DC battery will show too much voltage drop and take longer to start.

 

[donaldm]

Re: How fast should a 5.0 merc engine start?

I have two batterys. batt one i've been using for starting is a small size, deep cycle with no amp numbers on it. its labeled marine, rv, gulf cart. The second batt which i have only for backup but not used is bigger, labeled "marine cranking amp 1000" bought at auto zone and was told its a dubble use type. Ill try using the 1000 to start. Question any reason why I cant buy a second identical 1000 batt and run both at the same time in parallel

 

[Fun Times]

Re: How fast should a 5.0 merc engine start?

I have two batterys. batt one i've been using for starting is a small size, deep cycle with no amp numbers on it. its labeled marine, rv, gulf cart. The second batt which i have only for backup but not used is bigger, labeled "marine cranking amp 1000" bought at auto zone and was told its a dubble use type. Ill try using the 1000 to start. Question any reason why I cant buy a second identical 1000 batt and run both at the same time in parallel

You can run two batterys If you have a battery switch that has batterys, 1,all,2,& off, This way you can switch the batterys to run either battery or both batterys at the same time, As long as you set up the cables something like this diagram in this link. And yes you can have two of the same batterys as long as they are or at least one is 750 CCA or more to start the engine then you are good to go.

http://forums.iboats.com/showpost.php?p=2127575&postcount=7

 

[Don S]

Re: How fast should a 5.0 merc engine start?

You need a STARTING battery for your EFI engine, not a deep cycle. The combination batteries are part deep cycle and may still allow the engine to see too much voltage drop during initial starting.