2009 Speedster 150 SC tops 34 mph????

[xtremedesign10]

Im in Minnesota and took out my 09 Speedster 150 255hp SC and typically it will do 62+ at 7900 rpm. Today I could only hit 34 mph at 5900 rpm?? No cavitation noticed. The last time I had it out I had recently put a new wear ring on and prop, new oil in and everything to winterize it, it was running perfect. It only has 15 hours on it now. I also put the Stabil in the fuel, could that have anything to do with it? I know it's not the SC as I could hear it kicking in. Full throttle and it stays steady at 34 mph and 5900 rpm. I only have one key so I know it's not that, no smoke coming out the back?? Please help guys!!

 

[thor7000]

Check your oil level with the engine warmed up....sounds like you over filled it. I had the exact same problem with my speedster 150, would only do 35 miles/hr...checked the oil level and was above the full line, sucked some out and was able to hit 60!!

 

[xtremedesign10]

I was thinking about that, but I changed it last season at 11 hours, ran it another 3 hours at 60+ no problem. Sat over the winter and now I have this issue??

 

[devonte007]

Sounds like it is not reaching full rpms for some reason. You may also want to try a new set of spark plugs. I have have heard that old / bad spark plugs can make these engines run funny. I am guessing that there are no codes or engine lights on?

 

[xtremedesign10]

When I first start it up the maintenance light flashes like everything else.. but it goes away after 3 seconds or so. You think it needs new plugs even though it only has 15 hours on it?

 

[devonte007]

I am not sure about the maintenance light flashing at startup (since my boat does not have the digital gauge cluster) but the owners manual should tell you if that is normal. As long as there are no stored codes then you are probably alright.

As far as the plugs go, I can't guarantee that they will solve your problem but its a cheap easy place to start. I know they only have 15 hrs on them but looks like they are 2-3 years old. I replace my plugs every year regardless of how many hours I put on the boat. I think this is actually recommended in the owners manual as part of normal maintenance.

I would also make sure you have fresh gas in the tank, year old gas (even with stabil) can cause running problems. So start with new plugs, and fresh tank of gas. If that does not work, then you may need to investigate the supercharger and make sure it is performing properly. I know there are other threads on how to do that and its fairly simple.

Hopefully the simple things will fix your problem without the need to go down the supercharger avenue....

Let us know if you get any improvement.

 

[screwball]

Did you check your intake for weeds, plastic bags, ski ropes, etc. It makes no sense that it ran good last year and just won't run this year. Good Luck

 

[xtremedesign10]

Ok.. I just replaced the spark plugs and checked the oil. The plugs were probably over due.. and the oil is at a good level. I can't test the boat out as we are getting thunderstorms at the moment. There was oil on the bottom of the plugs too.. this may be the culprit!

I am a little upset as I had thought I would get out more at the end of the year and never did, and of course it has a full 26 gallons of gas in it with the Stabil... UGHHH

 

[xtremedesign10]

I did check to see if there was something around the prop..all clear! After I replaced the plugs I started it up... and noticed it started quicker without the slight hesitation it had when I was on the water. This is a good sign!!

 

[Dennis]

That middle spark plug is fouled. I think you found the problem. :cheers:

 

[thor7000]

agreed...plug is fouled, replace all three and you should be fine.

 

[seadooguynj]

Ok.. I just replaced the spark plugs and checked the oil. The plugs were probably over due.. and the oil is at a good level. I can't test the boat out as we are getting thunderstorms at the moment. There was oil on the bottom of the plugs too.. this may be the culprit! I am a little upset as I had thought I would get out more at the end of the year and never did, and of course it has a full 26 gallons of gas in it with the Stabil... UGHHHView attachment 11728

Middle plug fouled. Replace but also keep an eye on it to make sure this does not keep happening. If it does there could be a more serious issue.

 

[DonTom]

I was wondering if the plugs fixed our problem? I’m having the same problem. Things were fine when I put it up for the winter then first time out runs bad. Replaced all the gas, didn’t help. Checked intake for trash, none. Need help!!

 

[Harold Stovall]

Did the plugs fix your problem?

 

[Fred man]

Hey guys, not to steal this post but you guys mentioned that 7900 rpms this boat will do 60+. my boat seems to pull 8060 rpms? I have not let it run more that 5 secs with those rpms because it's still breaking in with 4 hrs on it. My question is, are these rpms too high? Thanks

 

[jkoziol]

I would also like to know if the plugs fixed your problem. I bought a 2009 180 challenger se 2555hp,40hrs on engine 3wks ago Took it out for test ride with dealer for about 40 mins. Bought boat. Took it out again that day for 60 mins until we got the low gas warning. The gas was from winterization. 2wks later took it out for the day with fresh tank of gas. No problem all day - got up 7900 45mph (high altitude). At en of day boat spuddered and lost rmp. Wouldn't go over 5200 21 mph. Turned the boat off - wouldn't start again. Sounds like trying to turn over but wont start. So wondering if it's plug, bad gas, or worse blown supercharger.

 

[chlarson23]

I have had my boat out twice so far. The first time my boat maxed out at around 6000 rpms. I changed my plugs and took it out again and it was back to its good old self. For everyone asking that is definitely where I would start. It's the easiest and usually cheapest place to start.