1987 Mercury 150. suggestions to increase performance

[captsparkie]

I have a stock 1987 Mercury 150. It currently has a 25" shaft, I have a jack plate, but I will want to change it to a 20". I am going to be putting this motor on my 2003 Sea Pro SV1900. It is a bay style boat. I am looking to do some simple and inexpensive things to increase its performance. I am not very familiar with Mercurys as I have mostly owned OMC. So any input would be appreciated even if it is simple.

Thanks
Captsparkie

[HStream1]

IMO before you try doing anything. Do or have a Compression done and maybe even a leakdown. Once satisfied that both are OK then you can do a couple of things. if they are not you're just throwing away money. The biggest bang for the buck is having heads cut to lower the CC's. That alone will give you more Bottom end and midrange. A good set of Reeds never hurts either. After that be prepared to start doing this $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$. Or if the boat's HP rating allows fine yourself a 2.5 200.

[outasite]

If your 150 has reed stops.I beleve the 200 vertical reed motor has a wider stop.And i see some of the models dont have stops at all.With proper jetting you mite see 10-15 hp.I just checked an old manifold i have (vertical)and they are set at about .350.I think that i have read that the 150 is way less than that.

[Dave Strong]

If your 150 has reed stops.I beleve the 200 vertical reed motor has a wider stop.And i see some of the models dont have stops at all.With proper jetting you mite see 10-15 hp.I just checked an old manifold i have (vertical)and they are set at about .350.I think that i have read that the 150 is way less than that.

Most aftermarket reeds don't use stops. The 150hp has a real long tuner, a short 200hp tuner can give a bit also but seems to help most if heads and reeds are also done.

Dave