Pulling the top cap as poker suggested is a good easy way for sure. I still think you should try the M+ 23". If you have a 1.36 and the power, speed should be 73-74 mph. If that is the case, get Bblades to lab it for you. Then 76-77+ would not be out of the way. Again that is only, AND only if you can get to 73-74 or so with a non labbed prop. If the 23" is way to easy to spin, then the next step is of course the 25. As pointed out, you need to find out if it is your prop that is the problem. Regarding tearing the motor apart. That was more in response to an earlier post, about wrong cam install. If you can't spin the 23" higher, then you have a motor issue. So try the prop, count your teeth, and go from there.

Let us know how it goes.

I checked the drive and it is a 1.5-1 drive. I found the issue why the motor will only turn up to 4400 rpm. When we dynoed the motor we had the timing set at 36 degrees. I had to pull the distributor due to oil leaking around the locking collar to put some silicone on it to stop it from leaking. I marked the distributor to make sure I put it back in the correct spot. We checked the timing this weekend and it was 39 instead of 36 and right after we turned it down the motor started a terrible tapping/knocking sound. I tore the motor down and had dropped a exhaust valve seat that destroyed 4 pistons. Now I am back to rebuilding the motor with new pistons, rings, bearings, and heads. This motor only had 2.7 hrs on it but it was my fault for not checking the timing immediately after I pulled the distributor.

Wow, sorry to hear:eek: Hopefully you'll get it sorted out, and get a good boating season anyway.

fwiw. I have an 89 272sr1 with bravo's and 25p @ 4600 its going 65mph on the wish o meter lol

Huh!???

:point:

the op was trying to figure out if he has 1.5 drives or not, so i figured Id post that to help

oh i see what happened, i posted before i read the whole thread LOL oops!