Engine checks out okay, only turing 3k rpms and 33mph at WOT

89cruisers

Petty Officer 2nd Class
Joined
Jul 11, 2005
Messages
190
Hey there everyone, like was suggested in the previous thread, I checked out my 188hp 302, Compression is good, points are gapped good, timing is set at about 6* btdc, and is going to about 30* at 3k rpms, carb opens all the way, and new plugs. The drive is set up for a 233hp 351, which would have a 1.5 ratio while I was told the 188 should be connected to an about 1.7 ratio drive. Adding a new gearset would be out of the price range, The boat currently has a 16x15 4 blade prop. Is there a prop I could use, such as a like 13x14, to get the speed and rpms up? Or could a 4 barrel carb with an adapter plate help bring the power up enough to get thru the low gearing? I ask becuase the 170hp 4 cylinder merc can be made to 190hp just by adding a 4 barrel. Your guy's professional input is very helpfull to me
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

An adapter plate and 4 barrel aren't likely to ad much if any power.A proper manifold and carb might ad 20 hp.Done right could help a little.
There is an 11" prop available might add 800 rpm.As a rule as pitch goes down diameter goes up.your not likely to find lower diameter props.A 13" wouldn't fit right.
I believe intended for a smaller gearcase.
 

89cruisers

Petty Officer 2nd Class
Joined
Jul 11, 2005
Messages
190
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

If a 13" is to small...is there any recomendations?
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

16" dia on there now?
so it must be a TR drive....

I don't think an MC1 drive can have a fan that big...

if you have a 19 tooth spline, you'll probably have to get what you have reworked by a prop shop.
 

89cruisers

Petty Officer 2nd Class
Joined
Jul 11, 2005
Messages
190
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

My prop on there is a 15x16 sorry, and there is nothing wrong with it, it looks almost new, I just need the speed and rpms higher
 

Howard Sterndrive

Rear Admiral
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Nov 5, 2008
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4,603
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

Iboats has a 15.5X13P Solas for under $100


SKU:#1511-155-13
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 15 - 1/2?
Pitch: 13?
Blades: 3
Rotation: Standard (Clockwise)
 

89cruisers

Petty Officer 2nd Class
Joined
Jul 11, 2005
Messages
190
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

Thanks for that, I will give that one a try maybe, do you happen to know if that will fit properly being a 15.5"?
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

I think it'll be ok.
As you go down in pitch, the blades are "flatter", so they're a safer distance away from the trim tab anode. I guess that's why lower pitch props seem to go up in dia.

My 20P prop is 14.5 and required me to notch the trim tab anode with my grinder.
Where my 17P cleared it just fine as it was.
 

89cruisers

Petty Officer 2nd Class
Joined
Jul 11, 2005
Messages
190
Re: Engine checks out okay, only turing 3k rpms and 33mph at WOT

oh alright, that's reassuring, will proably try going with that one then.Thanks for finding that. Im at work or school a lot so access te internet with my treo which isn't the best for online shopping lol
 
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