Nitro 901 CDX sluggish hole shot

[Deadeye]

Ok let's try and make some sense of this issue, just saw this thread.

While I am not a Prop Expert, I do know that the entire advantage and reason for the Pop-out Plugs is to allow to to add and remove to change the size of the hole.

What this does is add or reduce the amount of Exhaust that gets mixed into the water surrounding the actual Prop Blades. This added or reducing changes the Mix and allows for a much better hole shot when set correctly.

IMO Your height is fine. although it is a little high I think as 3 1/2 is standard starting point and you move up/down 1/4 inch at a time until you find the sweet spot. However lowering it will lower your RPMs.


Are you sure that your Plate does not also have adjustment holes? Some were just a set-back plate with no adjustments and some were so you could raise or lower the setting, then add the motor.



In any case I would by putting plugs with a Bigger Hole in them and see what happens. I'm betting that extra "air" around the Prop will make your hole shot much better.



EXTRA NOTE: At first reading your problem I was betting it would be a Bad Plug Wire. They tend to ground out on the Motor Head and that causes it to Short Out and loose power to at least one cylinder. I had that happen on mine and it went from running fine to like a slug. Changed out the bad wire and ran perfect again. BUT after seeing a Merc Tech checked out the motor and said it had good spark to all cylinders that rules that out.

[Bud Kennedy]

I still think a manual jackplate would be a good addition for you when it comes to adjusting motor height.  The rest of the problem remains quite a puzzle.  RPMs should be able to get 5500 - 5800 if the entire set up was right.  Entire set up for this conversation is still motor height and the other being prop.  Will be interesting what you find if you are able to test a different prop.

[Borkman]

Gents,

A few points.... I yanked one of the PVS plugs.  My hole shot has improved enough that I'm happy. 

My back bracket is not adjustable, per Deadeye's question.  It's just a 10" setback bracket.  My only adjustment is on the motor mount holes.  I'm in the #2 position.  I can go down to the #1 postion.  The Merc guy here said that the #2 hole is standard for mounting that motor.   

I appreciate the input.  My plan now is to run over to Brainerd, bass country, and test drive 23 and 24 pitch props.  If I can get the rpms up a bit, and not take anything off the top end, I'll purchase a new prop.  Otherwise, I think I'll invest in a jack plate.  I have a buddy with an engine hoist.  I've watched a few videos on it.  I think it should be straightforward to just install one myself with a few buddies and a few 6-packs to get them there.  Unless I'm being very naive here. .. . .   local shop wanted $600 for install of a manual jackplate, plus the $400 for the plate itself. 

Stay tuned, it may be a week or more before I'm able to test drive some props.

Again, thank you for your time and input . . .   Borkman

[apenland01]

Sounds like you got a good plan there.  Keep us updated!

[Deadeye]

Gents,

A few points.... I yanked one of the PVS plugs.  My hole shot has improved enough that I'm happy. 

My back bracket is not adjustable, per Deadeye's question.  It's just a 10" setback bracket.  My only adjustment is on the motor mount holes.  I'm in the #2 position.  I can go down to the #1 postion.  The Merc guy here said that the #2 hole is standard for mounting that motor.   

I appreciate the input.  My plan now is to run over to Brainerd, bass country, and test drive 23 and 24 pitch props.  If I can get the rpms up a bit, and not take anything off the top end, I'll purchase a new prop.  Otherwise, I think I'll invest in a jack plate.  I have a buddy with an engine hoist.  I've watched a few videos on it.  I think it should be straightforward to just install one myself with a few buddies and a few 6-packs to get them there.  Unless I'm being very naive here. .. . .   local shop wanted $600 for install of a manual jackplate, plus the $400 for the plate itself. 

Stay tuned, it may be a week or more before I'm able to test drive some props.

Again, thank you for your time and input . . .   Borkman

Sounds like your on the right track. Hope you find the one that makes it right.

BTW, on the actual Mercury Website there is a section called "prop selector or prop finder", don't remember which now. Anyway on it you can put in your information and they will give you the best props in their estimation for your set up.