port engine keeps dying at startup

0

07street

New Member
Jun 6, 2010
56
middle tn
Boat Info
97 300 DA
Engines
twin 5.7's v-drive
here's whats going on. when i first start the boat the port engine starts just fine and runs for a minute or two then dies. start it up again it runs for a minute or two then dies. after the second time it dies i have to pump the throttle a couple of times and it starts then dies. after doing this 4 or 5 times it settles and runs great the rest of the day. even after running the boat and then sitting all day in a cove it nevers acts up again that day however if the boat sits for a few days or a week its the same thing all over. im not a mechanic so therefore i dont even know where to start other than callling a mechanic out to the boat. hoping someone here can help steer me in the right direction on what this might be.


thanks for your replies in advance
troy
 
Hi Troy,

Did you ever find a solution to this? My port side engine is doing the exact same thing!

I’ve recently replaced the batteries and fuel filters, still happens.

Thanks!


QUOTE="07street, post: 589771, member: 15385"]here's whats going on. when i first start the boat the port engine starts just fine and runs for a minute or two then dies. start it up again it runs for a minute or two then dies. after the second time it dies i have to pump the throttle a couple of times and it starts then dies. after doing this 4 or 5 times it settles and runs great the rest of the day. even after running the boat and then sitting all day in a cove it nevers acts up again that day however if the boat sits for a few days or a week its the same thing all over. im not a mechanic so therefore i dont even know where to start other than callling a mechanic out to the boat. hoping someone here can help steer me in the right direction on what this might be.


thanks for your replies in advance
troy[/QUOTE]

07street said:
here's whats going on. when i first start the boat the port engine starts just fine and runs for a minute or two then dies. start it up again it runs for a minute or two then dies. after the second time it dies i have to pump the throttle a couple of times and it starts then dies. after doing this 4 or 5 times it settles and runs great the rest of the day. even after running the boat and then sitting all day in a cove it nevers acts up again that day however if the boat sits for a few days or a week its the same thing all over. im not a mechanic so therefore i dont even know where to start other than callling a mechanic out to the boat. hoping someone here can help steer me in the right direction on what this might be.


thanks for your replies in advance
troy
Click to expand...
 
image.jpg
cfd95 said:
IAC valve
Idle Air Control Valve
Click to expand...

Thanks, sir!

We (Amethyst and I) cannot seem to locate the valve, or muffler for that matter. Can you assist?
 
Last edited:
Perfect, thank you for clarifying so many things so succinctly!

Many thanks!
 
Any thoughts downstream in troubleshooting, in that case?
 
Make sure the throttle body is clean. Carbon buildup on the throttle plate can affect idle speed.

Does yours restart and run fine or will it not stay running?
 
It starts PERFECTLY the second time and only does this after sitting a day or more. Only acts up the one time starting either engine first. Fuel filters were cleaned and arrestors cleaned (today). We also just checked connection after installing 4 new AGM batteries. The next thing on my list was spark plugs but it didn’t make sense to me it would only affect cold starting.
 
My port engine does this too, but it's an older variation with IAC (and new IAC didn't help).

As Espos4 said, if the throttle plate has carbon build-up on the edge of it -- that can stick. If that's a shot of your engine, you can see the build-up. Clean that up with throttle body cleaner. See if you can work the throttle plate open/closed manually and it should be obvious whether or not it sticks. Which reminds me, I need to check mine :D

upload_2021-6-27_6-10-23.png
 
What I do in the meantime -- until I get it resolved -- is to run it at 1000 rpm for a few minutes when cold, until it's warmed up (normal idle is 600) then it's fine.
 
Thank you so very much, Phil, and Espos4!

We’ll be sure to report back our findings. These forums have been an absolute Godsend and I appreciate everyone being so helpful.

Cheers!
 
Phil S said:
What I do in the meantime -- until I get it resolved -- is to run it at 1000 rpm for a few minutes when cold, until it's warmed up (normal idle is 600) then it's fine.
Click to expand...
Same issue here, no IAC here, straight up carb. Bitch to start if sits few days, then i do what Phil does, high idle till gauge comes up then back it down. Starts quick for next few days, but let it sit til next weekend, same issue.
 
I just cleaned the inside of the tb and the throttle plate. And it helped idle after a cold start.
 
Last edited:
Gregory Beach said:
Thank you so very much, Phil, and Espos4!

We’ll be sure to report back our findings. These forums have been an absolute Godsend and I appreciate everyone being so helpful.

Cheers!
Click to expand...

Started right up— wow! Thank you for all your help!!
 
Awesome -- now get back out there and enjoy!

We had to bag it for today due to high winds :mad: Even my dock neighbors (who actually know what they're doing) decided to stay in.
 
Phil S said:
Awesome -- now get back out there and enjoy!

We had to bag it for today due to high winds :mad: Even my dock neighbors (who actually know what they're doing) decided to stay in.
Click to expand...

I hope you are able to get out soon, we're braving the heat wave here in western WA, triple digits this weekend through early next week.

:eek:
 
Phil S said:
Awesome -- now get back out there and enjoy!

We had to bag it for today due to high winds :mad: Even my dock neighbors (who actually know what they're doing) decided to stay in.
Click to expand...


Hey all, back again... :/

Performed throttle body and plate cleaning, and it worked like a charm- for one trip. We're back to the jump to 1000 rpm, then sputter and die. The second attempt is flawless every single time. It is happening to both starboard and port engines. It has never gone out on us on the water, or when warm, and seems to be worsening with each "fix" we apply. Anyone think it could be a vacuum leak resolved by the first attempt? Spark plugs? We're out of ideas now and don't understand enough to diagnose further. We have DTS (no IAC valve/filter), but do you know if we have any sensor which could beintermittent/failing without throwing a fault via SmartCraft/VesselView?

We have:
- replaced fuel filters
- stabilized and replaced fuel
- cleaned the throttle body and plate

Each time it has drastically succeeding turning on the first time, but only for that one time.

Thanks for anything and everything!
Greg & Ame
 
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