2001 speedster motor running poorly

[FastFive]

Hello everyone and thanks for taking the time to read my post.

Took the boat out for the first time this season on memorial weekend. It ran great on my initial run. I pulled back to the marina to fuel up. After leaving the marina the motor seemed to sputter or miss fire in differnt ranges of RPM but ran fine at idle. I figured that there was condensate in the tank or perhaps water in the fuel i got from the marina. the folling day i put a bottle of dry gas in the tank and went for a ride around the river. The boat ran perfectly with no sputtering or any issues.

I finaly got time of to take the boat out with some friends this past weekend. I filled the tank with fuel at a local gas station on the way to the marina to avoid paying the inflated gas prices at the marina. After launch and getting everyone situated on the boat i fired up and she purred like a kitten all the way to our destination swim spot which was about a 20 min ride at about 30mph the whole way.

After swimming for a bit we decided to do some skiing and tubing. This is when i started to have issues again with the motor. Same as before it would idle fine but would seem to periodically sputter or sound as though it was miss firing on a cyl. Would the temp sensor be the culprit? I like to turn the motor off as people board the boat from the water and a few times the motor would not turn over but the starter would.

Any help is greatly appreciated. Thanks

 

[El Toro 33809]

Our Challenger, with the Merc engine, would cut out sometimes around 4,000 RPM. We replaced the plugs and it is fine now. How old are your spark plugs?

 

[FastFive]

Our Challenger, with the Merc engine, would cut out sometimes around 4,000 RPM. We replaced the plugs and it is fine now. How old are your spark plugs?

Not sure. It engine had 35 hrs on it when I got it last August. I think the motor was replaced as the wear on the rest of the boat looked to be more than a 1000 hrs of use. Lol. Thanks for the input. I'll try replacing those.

 

[FastFive]

Anybody have any input on what the gap settings of the spark plugs should be?

 

[biffdotorg]

Anybody have any input on what the gap settings of the spark plugs should be?

Which motor do you have in your boat? I have the Mercury service manual that will tell us.

1mm is the norm and should be set from the factory if you buy the -10 spark plug.

This is assuming you are running the Merc 240efi engine. I can't say that I have seen too many speedsters with that engine though.

http://www.seadooforum.com/showthre...er-240-EFI-Engine-problem&p=406946#post406946

 

[FastFive]

Which motor do you have in your boat? I have the Mercury service manual that will tell us.

I have the Mercury M2 V6 240 efi

 

[biffdotorg]

I have the Mercury M2 V6 240 efi

Perfect, NGK BPZ8HS-10 with 1mm gap will do it.

 

[FastFive]

Perfect, NGK BPZ8HS-10 with 1mm gap will do it.

Thank you very much!

 

[FastFive]

Finally got out on the water after changing the plugs this past weekend. Thank you everyone for the help. Changing the plugs made a world of difference. Everything worked perfectly. I can only assume that these boats eat through spark plugs as i would not have expected to have an issue with them at only 40 hrs on the motor.

 

[Dr Honda]

Nope. They are normally very easy on plugs... assuming everything is adjusted proper. Last season, we had a guy with running issues... and the picture of his plugs showed black paint on the base. They were the factory plugs !!!!! (11 years old) I've personally run the same set of plugs in my engine, since my rebuild. (2 years ago)

If the oil pump is on the rich side.... If you run extra oil in the fuel... if you run poor quality fuel/oil... If the port side temp sender is bad... if the TPS is bad, or misadjusted... Excessive idling........... ect

Those can all cause the engine to run rich, and foul plugs early.


With that said... I still keep an extra set of plugs tucked in the boat.

 

[FastFive]

Nope. They are normally very easy on plugs... assuming everything is adjusted proper. Last season, we had a guy with running issues... and the picture of his plugs showed black paint on the base. They were the factory plugs !!!!! (11 years old)

Interesting as the plugs i had taken out were allso painted black on the base which i also assumed were factory plugs.

 

[Dr Honda]

Since you said the Hr's were low on the engine.... Generally you will find black paint on the plugs, if it was an OEM rebuild.