Recent content by Edstrossner

I got the motor back together and put some hours on it to break it in before I ran it at wot. The results were disappointing. I did a lot of work on the block and gained nothing. After the first run at wot I started to look at the exhaust area where it exits the prop. The aluminum props have...

I took the intake manifold off the 25 last week with the thought of adding a pair of cone spacers to the reed assembly. After removing the reed plate I noticed that there is a large difference in the crankcase openings. Cylinder #1 has a larger opening than cylinder #2. So, I decided to tear...

Thanks for the info. I new that an ss prop really helps on the larger hp motors but I have not tried one on the smaller motors. I'm running at 5900 rpm with a 4 blade, 14 pitch aluminum and with a few more mods I'll be at the pack limit of 6100 rpm. I know where I can get a 3 blade, 17 pitch ss...

I finally found a1982 35hp head. It looks like the one from the flyer. So, I bolted it up to my 2000 25 hp and I was a little disappointed. This motor with the stock head ran at 105psi. The 1982 head ran at 125psi. I had read that guys were getting 150psi with this head. Port timing on these...

I measured the piston dome at .625 from the deck to the dome at TDC. The head measures .650. The gasket adds .050 so at TDC the dome to head squish clearance is at .075. I like to run a squish clearance at .030 to .035. So from a stock head you can mill .040 off the head without any additional...

Omc lowered the minimum octane required for all the 2 cylinder cross flow motors down to 67. They where selling a lot of these motors to areas of the world that had poor gas. They may have opened up the ports to keep the hp rating the same. I have seen pics of the high compression 25/35hp head...

Has anyone tried using different cylinder heads for the 25hp? There are 4 different part numbers. 1980-81---324319 1982-------327672 1983-89---327671 1990-------335655 The 1982 head is supposed to be the best. 1990 and up is the low compression head. But, how good are the other 2 heads?

Thanks for the info! I did check the plugs when I came in. Since I started using the 70hp carb I have been increasing the main jet size. It was at 67 but it appears to be lean still so I just when up to 70. I also cut a hole in the hood in the area behind the grab handle, then I shimmed up...

We had a beautiful day here in Georgia and I took the Lowe out for a spin . I just finished modifying the head so it was time to see if the mod did anything. The answer is a definite Yes! Starting with the 1990 model, the cylinder head was changed to a low compression head. Apparently OMC was...

I think it was a 3/8" end mill that I used on the V-4's. It was a long reach to square off the exhaust ports and they did not make an end mill long enough in 1/4". I do not want to change the port timing on my 25hp. If I did change it, It would be to match up to the 30hp specs. It seems that...

The parts catalogue is a good start but I'll be doing some machine work to this block and it helps to know what OMC did in their port placement to get 30hp. I'll be squaring the ports with a 1/4" end mill and possibly opening up the passage way from the crankcase to the transfer ports. It's...

Great info! But I am looking to go farther in the 25 to 30 hp mod. I recently bought a 16 foot Lowe with a 2000 25 hp Johnson, 2 cylinder cross flow. The stock carb has a .875 Venturi with a 1.250 throttle bore. Wot is 5500rpm at 24mph gps. I had an old 70 hp carb with a 1.187 Venturi and a...