Low Idle Speed and Stalling

[breakthastatic]

So I bought an 06' SX230 HO project boat knowing it would be a can of worms. The port engine wouldn't crank when I bought it, but that was a bad clean out hatch switch bypass hack job (that's a topic for further down the road). Now it starts but won't really idle. If I try to rev it it stalls. I got a YDS cable and hooked up and it only wants to idle around 1100 to 1200 rpm. So I hooked up to the starboard engine, which was running when I bought it, and low and behold it also has low idle. The idle speed for these engines should be 1650 according to the sticker on the engine. I messed with the throttle stop screw on the port engine, and it does change the RPM, but not enough and the motor doesn't like it. However, I was able to see that the TPS looks functional as it showed the throttle opening as I turned the screw.

I put new spark plugs in the port engine, but that changed nothing.

I pulled the logs from YDS and attached them. The port engine log is with the throttle stop screw turned in. I can see both engines have had a low oil and over temp event, but everything is showing normal now, and the boat has had operational hours after the events.

I don't have much history on the boat, but I'm guessing it has sat for about a year. The previous owner did say the fuel had stabilizer in it. The previous owner also had aftermarket impellers installed if that could have any impact on idle speed.

I'm thinking bad gas, but before I got through the whole rigamarole of pumping out the tank I wanted to see what the jetboaters community thought. This is my first experience with boats.

 

[Cobra Jet Steering LLC]

Sounds like you have stale fuel smell it put your nose in the filler opening and you should be able to get a good wiff of it stale fuel has a distinct odor pull some out of the tank from the bottom / put it in a jar and let it sit just to be sure it does not have any water in it, if so it will sink to the bottom of the jar. Then siphon some out , empty your lawn mower tank and put some in the lawn mower if it runs like crap you have your answer.

 

[breakthastatic]

Sounds like you have stale fuel smell it put your nose in the filler opening and you should be able to get a good wiff of it stale fuel has a distinct odor pull some out of the tank from the bottom / put it in a jar and let it sit just to be sure it does not have any water in it, if so it will sink to the bottom of the jar. Then siphon some out , empty your lawn mower tank and put some in the lawn mower if it runs like crap you have your answer.

Thanks for the suggestions. Is pulling the fuel sender the best way to siphon from the bottom of the tank?

 

[Scottintexas]

Probably so just so you have better control of what your getting

if you end up having to drain the tank you can use the yds and disconnect the fuel line at the rail and pump it out

 

[breakthastatic]

Probably so just so you have better control of what your getting

if you end up having to drain the tank you can use the yds and disconnect the fuel line at the rail and pump it out

How do you get YDS to connect without the engine running? I've not had any luck getting it to connect with the ignition just on.

 

[Scottintexas]

It should when you turn key to run
It won’t give you live data but it gives stored info

Our search function is lacking
if you search on Google with this website only
Water fuel yds pump empty
The instructions may come up
Maybe it was member scubaref ??

 

[dgfreeze]

You need to "bump" the starter to get the YDS to connect up. You don't have to start the engine, but just key on won't do it either. Just give the starter a quick "bump", and it will connect up without the engine running. Did you do a compression test on the cylinders?

 

[breakthastatic]

You need to "bump" the starter to get the YDS to connect up. You don't have to start the engine, but just key on won't do it either. Just give the starter a quick "bump", and it will connect up without the engine running. Did you do a compression test on the cylinders?

Thanks for the info about YDS. I haven't done a compression test yet. I'd have to buy/rent a tester. I'm going to try replacing the gas first, which hopefully happens this weekend.

 

[dgfreeze]

I would recommend renting a compression tester to take with you, so if the fuel doesn't remedy the issue, you've got the ability to dive right into more testing. Hope for the best, plan for the worst. If it is bad fuel, it will have a pretty pungent smell to it. Varnished fuel is a distinctive smell, and you can distinguish it from good gas very easily. If you have to run compression tests, be sure to document the results. And be sure to have the throttles wide open for the test. Closed throttle will yield lower results. Can make a big difference, leading to going down an unnecessary rabbit hole.

*edit* and remove all spark plugs for the test. An engine should be spun with the starter, open throttle, and no spark plugs. Just be sure there's nothing to ignite any fuel mist that might get shot out of the cylinders.

 

[breakthastatic]

Update. Sucked all the gas out of the tank and put in 5 gallons of fresh. Both engine are now idling at 1600 rpm and rev nicely now. Thanks for everyone's input.