Isky tool room 9905 springs.. Crower Enduro SS rockers..

Silent Choice and 525's are NOT a good combination especially if the motor is close to the transom. This is what 525's do when you have Silent Choice. And before anyone chimes in and says this is from leaking headers, it's not. I've done extensive pressure testing on the headers with not a single leak. Using the Silent Choice is NOT the problem; the problem is that the reversion is caused by the tails being short and the water dump being too close to the collector and the exhaust pulse sucks the water back in when idling. This is a known issue with 525's and silent choice and another one of Mercury's dirty little secrets. Don't believe me? Call Mercury and ask them about Silent Choice and 525's and see what they tell you..

[ATTACH=CONFIG]533769[/ATTACH][ATTACH=CONFIG]533770[/ATTACH][ATTACH=CONFIG]533771[/ATTACH][ATTACH=CONFIG]533772[/ATTACH]

I've seen that on a few 525's that I've worked on.Your not alone.

Do you have the proper Z shaped divertors? They dump the water further downstream then the standard Y pipe does. I haven't had any issues and the Mercury 525 service manual says that Q&Q exhaust can be used up to 2,500 RPM. I only use mine sometimes at idle. Since my headers never get hot I also left the water flow restricters in place.

The Isky part number for stock spec replacement springs is 8005A.

did you happen to notice a ramp to reflect water some what.couple I did,had them.

Yep... my setup looks (looked) pretty much the same as yours. If you're not getting reversion, consider yourself lucky but it's something to really keep an eye on. I had absolutely no indication this was happening. I had been pressure testing my headers every 10 hours and had no reason to think there was any problem. Then I pulled the headers to do my valve spring replacement and this is what I found. I should also note that there wasn't a single speck on the exhaust ports of my center engine and that one does not have Silent Choice. I'm pointing this out to you for your information to hopefully save you and others from very costly repairs down the road. I'm having custom dry tails made and removing the silent choice; I've already replaced two long blocks in the last two years. I lost one on my 38 Fountain to leaking headers and one this season on my 47 to a rocker arm failure; trust me.. it sucks...

I can tell you this for sure: Merc. and CMI didn't offer the Silent Choice. Fountain, did that one their own. This was due to customer request, if you look at the down diverter tube, you will see, it's going in the opposite direction, than the normal install from what I see in your picture.
A friend of mine worked for Merc Racing for 32 yrs and was active in the project. He stated to me, they didn't want silent choice on that package and also speaking to someone else, highly involved at Fountain, stated to me the factory added the silent choice.

[ATTACH=CONFIG]533794[/ATTACH] This is a 47, I sent to Acapulco. The boat has CMI Aft Fire Mufflers, from factory. I think; Fountain, may have changed their thinking at some point.

Hy5, Is this caused from salt water usage? I get the reversion issues but the pics look like ports are all pitted. Again I get the reversion issues but the pitting is from salt water yes? My pics are not real clear so maybe I am not seeing it correct. The reason I ask is I also have a 525 / 47boat & 2 years ago I did not have these issues.
Thanks

That looks like someone added dry tails and mufflers... proving my point I think..