Trying to find missing WOT RPMs

[yjander]

It's worth a try to see how it reacts. Swapping spacers is remarkably easy. I wouldn't expect but maybe 2-300rpm change between all spacers and no spacers.

I’ll take them all out and see how it does. Thanks

 

[zipper]

I’ll take them all out and see how it does. Thanks

Other than that, the other things that come to mind are...Did you change the fuel blend? I mean, switch from ethynol fuel from the gas station to marina fuel, non ethynol. But I dont think it would drop rpms that much. That is the fuel part, now air...Is there anything blocking the air inlets behind the swim platform backrests? Do you leave your blowers on? Now spark. Where did you buy the spark plugs, locally or on line. There is such a thing as counterfeit spark plugs. I might try another set.
Lastly, you may be experiencing heat soak.

https://jetboaters.net/threads/superchargers-and-warm-weather.14040/

https://jetboaters.net/threads/2015-sx192-supercharger-clutch-fail.14692/

https://jetboaters.net/threads/sx-195-overheat-alarm-and-engine-shutoff.26868/

 

[yjander]

Other than that, the other things that come to mind are...Did you change the fuel blend? I mean, switch from ethynol fuel from the gas station to marina fuel, non ethynol. But I dont think it would drop rpms that much. That is the fuel part, now air...Is there anything blocking the air inlets behind the swim platform backrests? Do you leave your blowers on? Now spark. Where did you buy the spark plugs, locally or on line. There is such a thing as counterfeit spark plugs. I might try another set.
Lastly, you may be experiencing heat soak.

https://jetboaters.net/threads/superchargers-and-warm-weather.14040/

https://jetboaters.net/threads/2015-sx192-supercharger-clutch-fail.14692/

https://jetboaters.net/threads/sx-195-overheat-alarm-and-engine-shutoff.26868/

Thanks for the info and the links. Let me address the issues one at a time

So I have changed fuel sources from time to time. On memorial day, I filled up on the lake with premium ethanol free fuel. I normally full up at QT with 87 standard fuel. I've run the boat on 87 standard fuel since I've owned it and never had an issue. Then a few weeks ago I stopped and filled up on the lake again as well. So in the past 2 months, I've put in a mixture of premium ethanol free fuel and 87 10% ethanol fuel. I didn't think this could be an issue, but glad you brought it up.

I've always hated the stock air box on my boat, but I think its actually placed in the best position. The rear vents by the backrests are open and nothing restricting them. I think the CAIs that route the big K&N filter right next to the exhaust manifold are not doing any favors to the engine. The stock airbox sucks in air from right next to the scupper valve, which is pretty much furthest away from the hottest part of the engine (block and exhaust tubes). The blower is usually off, but I will start running with it on.

I got the plugs from Oreillys. NGK LFR6A. I went ahead and got some new plugs today from Napa. They only had the Denso copper ones, but I'm not going to mess with the gap on these.

I hope heat soak isn't an issue, as I installed a factory SVHO intercooler this winter. I am running with a single pilot hole. I know others have said to run an additional pilot relief and also to run a dedicated water hose from the strainer for the intercooler. I guess I want to see if the oil and/or plugs help out my RPMs. If not, then I'll run a dedicated cooling line for the intercooler.

My plan is to drain some oil from the block and then test on Saturday and see how that works. If it doesn't help out, i'll bring the extra plugs with me and change them out on the water and see how that does.

 

[yjander]

So I sucked about .5 quarts from the engine and also changed plugs to be sure. Put in water yesterday and immediately got 7650 rpm or so. Not bad considering I have L13 cone with 2 spacers.

Unfortunately, after being out on the lake all day and running for about 45 minutes, I was back to only 7,000 rpm. So I have some heat soak issues, but disappointed since upgraded to SVHO intercooler. I plan on running a dedicated cooling line from the pump to the intercooler and see if that helps. If not, I guess i'm going to have to go fizzle or some aftermarket upgrade....

 

[yjander]

So finished adding a dedicated intercooler line tonight. It wasn't too bad. Went with the Riva strainer that was pre tapped. Ran a half inch heater hose to a barbed thru Hull fitting and then connected existing intercooler hose to the new hose. Had to use a 5/8 to 1/2 reducer because the thru Hull I had was half inch and existing intercooler hose is 5/8. Hope it doesn't cause any problems with the reducer.

Edit: added some pics from inside clean out area.

 

[yjander]

So finished adding a dedicated intercooler line tonight. It wasn't too bad. Went with the Riva strainer that was pre tapped. Ran a half inch heater hose to a barbed thru Hull fitting and then connected existing intercooler hose to the new hose. Had to use a 5/8 to 1/2 reducer because the thru Hull I had was half inch and existing intercooler hose is 5/8. Hope it doesn't cause any problems with the reducer.

Edit: added some pics from inside clean out area.

So this didn't work. Can't get above 7000 RPM. Super strong stream coming from the intercooler relief. Nice and cool.

Very frustrating. I guess it's time to really look at wear ring and impeller.

 

[yjander]

So this didn't work. Can't get above 7000 RPM. Super strong stream coming from the intercooler relief. Nice and cool.

Very frustrating. I guess it's time to really look at wear ring and impeller.

Seem to be suffering from heat soak. Went out today first thing had 7650 rpm and about 49. After a day of sitting and cruising, only had 6900 rpm and 40 mph. Thought the svho intercooler would help me. Guess I need to get a fizzle intercooler or another brand.

 

[bikerman5345]

Thanks for the info and the links. Let me address the issues one at a time

So I have changed fuel sources from time to time. On memorial day, I filled up on the lake with premium ethanol free fuel. I normally full up at QT with 87 standard fuel. I've run the boat on 87 standard fuel since I've owned it and never had an issue. Then a few weeks ago I stopped and filled up on the lake again as well. So in the past 2 months, I've put in a mixture of premium ethanol free fuel and 87 10% ethanol fuel. I didn't think this could be an issue, but glad you brought it up.

I've always hated the stock air box on my boat, but I think its actually placed in the best position. The rear vents by the backrests are open and nothing restricting them. I think the CAIs that route the big K&N filter right next to the exhaust manifold are not doing any favors to the engine. The stock airbox sucks in air from right next to the scupper valve, which is pretty much furthest away from the hottest part of the engine (block and exhaust tubes). The blower is usually off, but I will start running with it on.

I got the plugs from Oreillys. NGK LFR6A. I went ahead and got some new plugs today from Napa. They only had the Denso copper ones, but I'm not going to mess with the gap on these.

I hope heat soak isn't an issue, as I installed a factory SVHO intercooler this winter. I am running with a single pilot hole. I know others have said to run an additional pilot relief and also to run a dedicated water hose from the strainer for the intercooler. I guess I want to see if the oil and/or plugs help out my RPMs. If not, then I'll run a dedicated cooling line for the intercooler.

My plan is to drain some oil from the block and then test on Saturday and see how that works. If it doesn't help out, i'll bring the extra plugs with me and change them out on the water and see how that does.

I know this is an old thread but you said you got LFR6A for the SVHO engine and that is wrong. You need LFR7A for the svho engine. Also the SVHO will derate if you do not run 91 or higher octane fuel. 87 Octane will cause the knock sensor to change the timing and reducing performance.

 

[yjander]

I know this is an old thread but you said you got LFR6A for the SVHO engine and that is wrong. You need LFR7A for the svho engine. Also the SVHO will derate if you do not run 91 or higher octane fuel. 87 Octane will cause the knock sensor to change the timing and reducing performance.

I have a 2014 192. It has the SHO engine

 

[IvanS]

Check the air filter and make sure you didn't overfilled the oil. I had the same issue, I took the extra oil and now I see 8300 rpms in my SC engine