Need your info and advice on drive engagement
 

I have a Fountain we just put a set of 557ci 750hp motors N/A in with Xr's with Stelling boxes, right now the motors idle at 900 rpm and drop to 600 rpm when in gear, they go in and out of gesr very smooth no clunk or bang. I have 1:36 drives with 30 5 blade maxis props, we have 1050 dominators on the motors so its important to keep the vacuum up to keep the power valve from opening at idle and causing them to flood out. Do you think 900 is to high for engagement and what do your motors idle at when you put them in and out of gear? Thanks in advance.

900rpms is not a problem. 1000rpms or more and it will be hard on them.

I have 575SCi's ( slightly mod'ed)
1.5 XR's with stelling boxes and 32 maximus's.

The idle is set at 900 rpm's and it shifts fine.

I have the same issue. Depending on the temperature, run time, etc. my 572's do not want to idle below 1000 rpms's at times. Depending on my surroundings, I try to start them in gear when I can. Too much time around the outboard guys I guess?

I've owned and worked on Bravo boats shifting anywhere between 700 and 1100 rpms. Once you get to 1000 rpms level it starts to slam the clutch into the cone a bit.

With the right set-up of carb, power valve and vacuum you should be able to get it to shift. That is of course you don't have an extremely radical cam with a load of duration up in the 700's lift.

Should be fine...mine have been doing that for 4 years/186 hrs.

Having mentioned leak-down due to vacuum and powervalves, what powervalves are you running?

You may need to bring them down to 4.5's or 5.5's if you're running 6.5's. If you still can't get it right, adjust the secondary butterfly (small set screw) to open a little bit and that should help with your idle quality.

been there done that had same problem with 510 ci mega blower, double check timming and check vacume, had to go down on power valves and slightly open hole in throtle plates.

have ya played with the idle screws,does your model have a mid circuit,ck the throttle blades are set the same,

ya might have to play with the fuel idle restrict ors if ya have the jets,thats a pain in the ass