• Welcome to the Checkmate Community Forums forums.

    You are currently viewing our boards as a guest which gives you limited access to view most discussions, articles and access to our other FREE features.
    By joining our free community you will be able to:

    » Interact with over 10,000 Checkmate Fanatics from around the world!
    » Post topics and messages
    » Post and view photos
    » Communicate privately with other members
    » Access our extensive gallery of old Checkmate brochures located in our Media Gallery
    » Browse the various pictures in our Checkmate photo gallery

    Registration is fast, simple and absolutely free so please, join our community today!

    If you have any problems with the registration process or your account login, please contact support by clicking here or by using the"contact us" link at the bottom of the page.

First time out

justonemore

New member
Running a 150 efi on a Pulse 170. Turning a Tempest Plus 24"p. (Smallest prop I have). 4800 rpm @ wot, 55 mph on speedo with bow cover.
Have 4" setback, Pad is 2 3/4 " below cav plate which puts prop shaft 5 1/2" below pad. Defiantly over propped. Any suggestions?
 
Not sure what rpm range your engine is rated at. My math says a 22P Tempest would turn around 5240rpm. A 20P Tempest (if they make them) should be closer to 5760 rpm. If you switch to a smaller diameter prop the rpm might increase more than what I suggested above.
 
I had a Pulsare 1850 with a 150hp on it. 22“ Tempest was not a great prop from the factory unless reworked by a prop shop. A worked 22” is absolutely perfect if you can find one that has been cupped a little. I ran 66 mph with the 22”. A 21” Tempest should put you right near the limiter and put you low 60’s. You ar also way too low. Start the prop shaft around 3” below pad and work from there. I hope you have a water pressure gauge. You could also plug the top 2 or 3 water pick up holes. Mercury sells a kit, or carefully tap the holes with 5/16“ tap half threads and use matching thread 5/16” x1/4” stainless set screws with red thread lock.
 
Last edited:
I'm shooting for 5500 rpm @ 60+mph. I ran the tempest because it's what I had laying around. Is there a better option? Mirage plus?
Have Pressure and temp gauge with two holes plugged. I have to pull the engine off again anyway so I'll raise it up one hole. That should put me at 3 1/2 ". Unfortunately I live in Wisconsin and good days to run a boat are getting less. Thanks G, Thanks M.
 
I'm shooting for 5500 rpm @ 60+mph. I ran the tempest because it's what I had laying around. Is there a better option? Mirage plus?
Have Pressure and temp gauge with two holes plugged. I have to pull the engine off again anyway so I'll raise it up one hole. That should put me at 3 1/2 ". Unfortunately I live in Wisconsin and good days to run a boat are getting less. Thanks G, Thanks M.
The engine height should be a good starting point. Your boat is light, so it probably would be faster with smaller diameter prop that has less blade area than the Mirage. A 13.25" diameter Laser II might turn up good, but sometimes they have high slip. I think they make them in 19, 20, 21, and 22P. If you can find a 21P or 22P to try that might be worth a shot and so would a Fury. The ProMax is a fast prop that loves to run high (I have a 24P ProMax and a labbed 26P ProMax on order) but I think the lowest pitch them make them in was 22.5"P. An older chopper prop would likely be worth a try if you can find one. Not good for water skiing, since the over the hub exhaust will cause some slippage on take off until it hooks up, but then tremendous bow lift and good top end.
 
The engine height should be a good starting point. Your boat is light, so it probably would be faster with smaller diameter prop that has less blade area than the Mirage. A 13.25" diameter Laser II might turn up good, but sometimes they have high slip. I think they make them in 19, 20, 21, and 22P. If you can find a 21P or 22P to try that might be worth a shot and so would a Fury. The ProMax is a fast prop that loves to run high (I have a 24P ProMax and a labbed 26P ProMax on order) but I think the lowest pitch them make them in was 22.5"P. An older chopper prop would likely be worth a try if you can find one. Not good for water skiing, since the over the hub exhaust will cause some slippage on take off until it hooks up, but then tremendous bow lift and good top end.
My Eluder and Enchanter didn't like the Laser I had (23p) at all. The best prop I have is unfortunately not able to be identified (only ID is 25P engraved with a Dremel on the side) but it ran great on every Checkmate I've had with Merc outboards from 150-175 (both speed and lack of slip.)
 
I think the enchanter was around 20 - 21ft and weighed around 1300 lbs and I would guess his Pulse 170 is a couple hundred pounds lighter. That might just allow the Laser to perform with lower slip. The Tempest has plenty of blade area for his weight and HP, but some of the smaller props might be worth testing. A bit more setback like 6" might help as well. If he can turn a 21 Tempest, he might be able to turn a 22-23P Laser. A Fury is another smaller diameter prop that might work good with lower boat weights.
 
Been searching for props and there are a lot of laser's and high pitch tempest's out there.
If I can find a couple different props for a good price I'll start there.

Boat is 1100 lbs. With current setup i get extreme bow rise starting out. Once planned out there's plenty of trim range. And on hard turns it feels like the stern is going to come around.
Thanks guys
 
Been searching for props and there are a lot of laser's and high pitch tempest's out there.
If I can find a couple different props for a good price I'll start there.

Boat is 1100 lbs. With current setup i get extreme bow rise starting out. Once planned out there's plenty of trim range. And on hard turns it feels like the stern is going to come around.
Thanks guys
I think a lower pitch, especially a prop with a diffuser ring, will improve the bow rise coming on the plane. If your boat wants to porpoise at cruise speed even with negative trim, then you do not want more setback. The only way to find out is to try, and since the Tempest appears to be in the ball park except for the pitch that might be a good one to try first. Once you get the rpm and mph from that prop, you could try smaller diameter props like the Laser. If you can buy them cheap and they are in good shape you can sell them again and get most of your money back. A 4 blade Trophy is a small diameter as well and should blow that boat out of the hole. It might be 1 - 2 mph slower than the Tempest, and it might be as quick, only one way to find out. I have a 2400 Pulsare with a 300R, and Randy Corson's prop of choice for that same boat but with a 2 stroke 300XS was the 25P Trophy Plus and that boat with the engine, battery, fuel and driver was likely around 3000 lbs. I don't think the Trophy would work good on my 300R. Sometimes a dealer or marine repair shop will have some used ones in stock that they will let you try.
 
Back
Top