I bought the motor with worn out prop running 3600 rpm in the water wide open. I put a new 9x6 prop on it yesturday at 3300 in the water. I feel like there is more there but not sure what an average rpm range for my motor typically

Buddy of mine bought a 25 gdlt and gd sent him a 9-6. Said the 9-6 has been redesigned and the 25would NT turn the 9-7. Hope this helps

Broadriverboy,

What size boat is it on and is it a mv or true flat? A true flat 16x48 riveted jon with two 180# men and no load should run 3450 with a new 9x6 prop. Speed with this load and rpm should be 18,19 mph. On a riveted 1542 same load a little higher rpm and 1mph more. I have had engine on both. Once prop wears from grinding on bottom rpms will increase, I replace around 3750-3800.
Make sure your head gaskets are not torn as a small tear will kill some rpms. Turn motor 4000 out of water

What he said ^^^^

It's on a 1548 alwelded g3 MV plainer of its sitting on the flat part of the bottom with a brand new hills prop. I'm waiting on the go devil prop to come in, some say they run a little faster. The throttle cable a the lever seem like it is mushroomed back and I'm sure I'm losing so throttle there. Would mods such as carb & exhaust help a good bit or not really worth trying that? I know the boat is not te right set up but I would like to get by for two years until I can buy a go devil rig

Huck Finn
How do you like that duck skiff does it handle jumping logs good as far as leaning?

I would not modify your engine. Motor is fighting your MV hull.

Love my skiff , just switched from 16 to 25 horsepower , this week , have been tweaking a few things today. It's been in and out the water all day . As far as being stable , I'm careful . But it will go just about anywhere, and light enough I can spin it around or drag it out by myself .

H Finn

I'm running a 23 long tail on a 16x48 flat. I'm only turning 3,000rpm's in the water but my speed is pretty good 18.4 on GPS with just me and dog. Should I tweak my rims to run them a little higher?

I run a 23 GDLT on a 16x42 weldbilt. I have tried the Hill props and find Go-devils props are better. Set your rpm to 4000 out of the water and make sure your valves are adjusted correctly. Adjust you cav plate so your running as shallow as possible without popping out of the water. I can turn a 9x6 3630 to 3720 at 19-21mph with two 185 lb people. Only mod is slightly ported heads and a k/n drop in air filter.

What do I adjust the valves to I believe they are out of wack a bit. Do I ajust the cav plate up perhaps 1/4 of in at a time? My boat is a semi modified v and the water is on the flat bottom on plane so I don't think the mod v is hurting me but I may be wrong

Also how do I adjust the rpms to get 4k out of the water currently running 3600 to 3700 rpms. Only think I can think of to get 4k is to tighten the gov spring is that correct?

I bump 4200 RPMs on my GTR23. Not sure that translates to a longtail. That's with a cam, heads, carb and exhaust performance parts

with throttle in closed position bend the tab towards front of boat. go a little at time, a small bend should get you to 4000. I would not go over 4000 in a stock engine.

Got it running pretty good tried it out in some thick hyson grass this weekend Floated the boat after 15 or 20 min we were back at it riding thru the timber highes I seen the rpms was 3600 at 18 mph with me ( 170lbs) another buddy maybe (120lbs) soaken wet and a 50 quart cooler full of beer and ice don't seem to bad to me. I hope I can see 20 with the same load when my gd prop comes in thanks for the help guys

I have a 23 kohler on a 16x48 marshunter. I run 3850 in the water and 3950 out.

My stock vanguard 23 turns 4200 out of water and 3700 in water with a decent load in a mod v 1448 Lowe.