SOS! Starboard Engine Not Starting

[Ray Gallagher]

So I have a 1988 Sea Ray Amberjack 270 fitted with two i/o mercruiser 5.0 bravo III stern drives with fuel injection system. Engines have about 700 hours on them. Ran a compression test at end of season last year and everything was in good order. Spark plugs looked good. Marina winterized it, used fuel stabilizer, all the stuff your supposed to do. The marina changed the filters and fuel/water separators this year. Took the family up this past weekend, started great, ran great for about 30 minutes then poof starboard engine is gone once we got down off plane. Thinking it could be a fuel issue I switched the fuel for the starboard to the port side tank and it started right up... lasted a whole 2 minutes then stalled out again. So now I've ruled out the possibility of having one bad tank cause it won't work on either tank even though the port engine runs just fine. Limped back to the dock with one engine (thank god we had 2.. redundancy for the win). Still couldn't get it started again.. turns and turns but won't start. Kind of worried I might've done some damage trying to start it cause we got a nice little puff of blowby after a few more tries. Packed it up, went to the bar and drank about it for a while. Now I'm here! I've seen a few people mention IAC valve could be bad. Is that a good place to start? Would like a few things to try since the boat is about an hour away from me and I'd rather have everything I need for the day of repairs. Thanks in advance!

 

[mrsrobinson]

"So now I've ruled out the possibility of having one bad tank cause it won't work on either tank even though the port engine runs just fine"

You may not have. Pull the plugs, fog the cylinders, turn the engine over to blow them out, reinstall plugs, new fuel/water separator, try again on the known good gas tank. If it works, switch over to the "maybe" bad gas tank.

Doesn't sound like IAC to me.

 

[Ray Gallagher]

Kinda nervous to even crank it again after the hiss and smoke that i'm assuming was blow by. don't want to flood it. is that why you are suggesting to pull the plugs and blow them out?

 

[mrsrobinson]

Correct, fog the cylinders first before turning it over.

 

[Pirate Lady]

Packed it up, went to the bar and drank about it for a while. Now I'm here!

I got nothing to offer for the engine, but damn I sure like your Plan B! Been known to do the same. Salvage the day!

 

[Pirate Lady]

Correct, fog the cylinders first before turning it over.

Wait? Won’t that put more gunk on the plugs and make it even harder to start.

 

[Lazy Daze]

If it's the IAC that's the culprit, you can usually still start the engine with the throttle (only) advanced. You could also try swapping from port to stbd.

 

[mrsrobinson]

Wait? Won’t that put more gunk on the plugs and make it even harder to start.

Not if you leave the spark plugs out while you're turning over the engine.

 

[mrsrobinson]

If it's the IAC that's the culprit, you can usually still start the engine with the throttle (only) advanced. You could also try swapping from port to stbd.

Yup, two screws and a wire connection, and you can swap them.

 

[Ray Gallagher]

The spark plugs on these engines are in such a horrible location I'm dreading that solution. Really hoping I find something obvious when I head up later today so I don't have to do all that :/

 

[Ray Gallagher]

If it's the IAC that's the culprit, you can usually still start the engine with the throttle (only) advanced. You could also try swapping from port to stbd.

Try swapping what from port to starboard? You mean switch the IAC valves to see what happens?

 

[mrsrobinson]

The spark plugs on these engines are in such a horrible location I'm dreading that solution. Really hoping I find something obvious when I head up later today so I don't have to do all that :/

Do yourself a favor and go ahead and purchase new plugs when you do this so you don't have to go thru this again to replace them when it's time.

IAC is a torx screw from what I recall, make sure you have a torx socket/wrench.

 

[mrsrobinson]

Try swapping what from port to starboard? You mean switch the IAC valves to see what happens?

Correct

 

[Ray Gallagher]

Well it wasn't the IAC (damnit). Double checked the filters and all is good there. Definitely getting air and spark so I'm on to fuel diagnosis next. I'm thinking bad fuel or bad pump. This stuff really sucks when your boat is docked 90 minutes away from you and you work full time. Not to mention I got distracted by the fact that the outlets weren't working and spent a good 20 mins trying to find where they hid the gfci. Then there's the lovely new dock neighbor that thinks the electricity at the marina is free and decided to plug into one of my power sources.

 

[mrsrobinson]

Yes, it is frustrating when the boat is not close.

My first few boats were close so I could check, come back, try again, check, and be ready to go by the weekend. It's one reason I gave a lot of the fixes/service to the marina with my last 3 boats, so I could actually use the boat on the weekends after driving 90+ minutes.

Pull the plugs, fog the cylinders, turn the engine over to blow them out, reinstall new plugs, new fuel/water separator, try again on the known good gas tank. If it works, switch over to the "maybe" bad gas tank.

 

[Ray Gallagher]

Turned out to be a corroded distributor cap and fried rotor. Switched them out and she fired right up. Thanks for the suggestions everyone

 

[Pirate Lady]

Not if you leave the spark plugs out while you're turning over the engine.

I missed that part while speed reading the thread.