I recently bought a used SX192 for a great deal. I actually wanted a 190 but the deal on the 192 was good enough I could not pass. On the test ride it was very rough and we got up to around 41 MPH and 7100-7200 rpm. After purchase I took it out with a full tank and it got up to a GPS measured 43 and would see no higher than 7100-7200 rpm. I had already done some reading here and elsewhere describing the issues with the 192 and felt confident I could recover the lost speed by going over the boat and checking all the little issues as well as do the ribbon delete and SVHO intercooler upgrade.
So I made my list, ordered an SVHO intercooler from ebay and a ribbon spacer ring from Riva.
Last week I spent the day removing the ribbon/flame arrester and installing the SVHO intercooler.
Also adjusted the throttle cable to ensure it was hard on the stop. Installed a cheap mechanical boost gauge where the fogging line was. Changed plugs. I also cleaned the intake tract. There was quite a bit pf fogging oil coating everything from the previous owner.
Took it out today with 3/4 tank and 2 people and immediately I saw 7800rpm on initial throttle up. I did not have the GPS on at that point so I didnt get a speed. But I took it around the lake for about 15 minutes and did a top speed run and saw a GPS high of 49mph and 7500-7600 rpm steady. Little mechanical boost gauge read 6 psi. Intake and intercooler both hot to the touch.
Did about 3 more runs all ending with 49 mph. Conditions were minor chop and decent. Air temp about 78 and water temp probably 70. Fuel at 3/4 tank.
Acceleration was MUCH better and the boat came on a plane much quicker and throttle response much more crisp.
I do not consider this a gain in speed and HP. I consider it recovering what should have been there to begin with. I have no interest in going any faster.
In another life I was into drag racing and engine building/modding. I do not consider these minor mods to be invasive or risky provided they are done by a reasonably proficient mechanic/owner. I highly recommend these steps to any 192 owner that isnt getting the 48-50mph they should. Especially the OEM SVHO intercooler upgrade. This to me is a no brainer.
One other thing...I saw something about a fogging TSB. I have not read that yet. But I do consider some of the problem to be oil from fogging in the intake tract. Especially in the intercooler and ESPECIALLY in the flame arrester. The flame arrestor has so much surface area that introducing any fluid with any kind of viscosity will have a hard time shedding it due to surface tension/viscosity. I really think if someone did flow checks on the flame arrester clean and oil free, and then fogged with oil you would see a drop in flow. Fogging through this flame arrestor...then letting it stit coated for 6 months seems like a terrible idea to me. Same with intercooler. Just my opinion.
See the max speed in upper rh corner of the screen shot. This is the same GPS used to measure the previous 43mph run. 6 MPH swing. Conditions essentially the same between the two runs.
Hope this helps someone else.

So I made my list, ordered an SVHO intercooler from ebay and a ribbon spacer ring from Riva.
Last week I spent the day removing the ribbon/flame arrester and installing the SVHO intercooler.
Also adjusted the throttle cable to ensure it was hard on the stop. Installed a cheap mechanical boost gauge where the fogging line was. Changed plugs. I also cleaned the intake tract. There was quite a bit pf fogging oil coating everything from the previous owner.
Took it out today with 3/4 tank and 2 people and immediately I saw 7800rpm on initial throttle up. I did not have the GPS on at that point so I didnt get a speed. But I took it around the lake for about 15 minutes and did a top speed run and saw a GPS high of 49mph and 7500-7600 rpm steady. Little mechanical boost gauge read 6 psi. Intake and intercooler both hot to the touch.
Did about 3 more runs all ending with 49 mph. Conditions were minor chop and decent. Air temp about 78 and water temp probably 70. Fuel at 3/4 tank.
Acceleration was MUCH better and the boat came on a plane much quicker and throttle response much more crisp.
I do not consider this a gain in speed and HP. I consider it recovering what should have been there to begin with. I have no interest in going any faster.
In another life I was into drag racing and engine building/modding. I do not consider these minor mods to be invasive or risky provided they are done by a reasonably proficient mechanic/owner. I highly recommend these steps to any 192 owner that isnt getting the 48-50mph they should. Especially the OEM SVHO intercooler upgrade. This to me is a no brainer.
One other thing...I saw something about a fogging TSB. I have not read that yet. But I do consider some of the problem to be oil from fogging in the intake tract. Especially in the intercooler and ESPECIALLY in the flame arrester. The flame arrestor has so much surface area that introducing any fluid with any kind of viscosity will have a hard time shedding it due to surface tension/viscosity. I really think if someone did flow checks on the flame arrester clean and oil free, and then fogged with oil you would see a drop in flow. Fogging through this flame arrestor...then letting it stit coated for 6 months seems like a terrible idea to me. Same with intercooler. Just my opinion.
See the max speed in upper rh corner of the screen shot. This is the same GPS used to measure the previous 43mph run. 6 MPH swing. Conditions essentially the same between the two runs.
Hope this helps someone else.

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