Here is my problem. I have a four winns horizon 200 with a 350 OMC and Cobra outdrive. The gear ration is 1.5 to 1. The first time I took the boat out it would only hit 3000 rpms. Found out the tach was off by 1000 rpms. The shop I have work on it was able to get it within 300 rpms. They also checked the timing and found it was off and reset it and did the points and dwell. My rpms went up to 4000. With the tach off I was at an estimated 4300 which is close to where it should be. The prop was a 15X17 aluminum and top speed on the speedo (gps speed coming soon) was 32 mph. Elevation of the lake is at an ellevation of 3250 feet. I ordered a 14.25 X 19 4 blade to see what it would do and see what my speed would be. I have not run it at the same lake, but did take it up to another lake at 4700 feet. The boat dogged out of the hole but did run 35 mph at only 3100 rpms. In looking through the boat I noticed a couple of things.
The previous owner put a new 350 in it when the previous block had freeze damage. I noticed that he used all of the old parts he could and that is has a 2 barrel carb on it from the 305 that was in it. I am wondering what effect the 2 barrel and associated intake manifold will have on power since the 350 should have a 4 barrel.
I wanted to get your guys opinions. Should a 15X17 prop on a 350 be over propped at my elevation is that actually close to the right prop?
Should I be looking at getting a new intake manifold and 4 barrel carb?
I am thinking I need a new tach and I am getting a gps tomorrow so I can get accurate speed numbers.
Just trying to make sure the boat is getting the power it should.
On a side not my uncle has and old Beachcraft with a strong running 302. We ran side by side at the lake at 4700 feet. He has a 18 foot boat and I have a 20'9" boat. He had a 15X17 stainless prop and I had my 4 blade 14.25X19 aluminum prop. I was able to out run him at wot by about 4-5 mph.
Sorry for the long post, but I wanted to give as much info as possible.
The previous owner put a new 350 in it when the previous block had freeze damage. I noticed that he used all of the old parts he could and that is has a 2 barrel carb on it from the 305 that was in it. I am wondering what effect the 2 barrel and associated intake manifold will have on power since the 350 should have a 4 barrel.
I wanted to get your guys opinions. Should a 15X17 prop on a 350 be over propped at my elevation is that actually close to the right prop?
Should I be looking at getting a new intake manifold and 4 barrel carb?
I am thinking I need a new tach and I am getting a gps tomorrow so I can get accurate speed numbers.
Just trying to make sure the boat is getting the power it should.
On a side not my uncle has and old Beachcraft with a strong running 302. We ran side by side at the lake at 4700 feet. He has a 18 foot boat and I have a 20'9" boat. He had a 15X17 stainless prop and I had my 4 blade 14.25X19 aluminum prop. I was able to out run him at wot by about 4-5 mph.
Sorry for the long post, but I wanted to give as much info as possible.