Mariner 175 efi Prop help

**Jbone86** · 08-01-2021, 04:39 PM

Hi all,
Just bought a new to me 1997 Actioncraft 1802 with a Mariner 2.5l 175hp EFI. I am looking for top speed.

Heres what I am seeing with 2 adults, light on fuel, trolling motor, 4 batteries on board total. Trimmed up with tilt and jack plate: 46.5 mph at looks to be about 5700 rpms. The current prop is a Laser 2 25p. TIA.

Thanks,
Jason.

**Capt j** · 08-01-2021, 08:58 PM

Action Crafts seem to really like a Tempest +, try that in 25" or 24"

**Pulsare2400** · 08-01-2021, 10:41 PM

[QUOTE=Jbone86;3299530]Hi all,
Just bought a new to me 1997 Actioncraft 1802 with a Mariner 2.5l 175hp EFI. I am looking for top speed.

Heres what I am seeing with 2 adults, light on fuel, trolling motor, 4 batteries on board total. Trimmed up with tilt and jack plate: 46.5 mph at looks to be about 5700 rpms. The current prop is a Laser 2 25p. TIA.

Something seems off. Do you have a 1.87 gear ratio? If I use that ratio and your tach is accurate, it works out to 35% slip. It can't be that bad?? Either I am wrong using the 1.87 gear ratio, or your tach or speedometer is off. If all of them are really correct, including my assumption of a 1.87 gear ratio, you need to change the prop or whatever is causing the excessive slip.

**Jbone86** · 08-01-2021, 10:45 PM

[QUOTE=Pulsare2400;3299574]

Originally Posted by Jbone86

Hi all,
Just bought a new to me 1997 Actioncraft 1802 with a Mariner 2.5l 175hp EFI. I am looking for top speed.

Heres what I am seeing with 2 adults, light on fuel, trolling motor, 4 batteries on board total. Trimmed up with tilt and jack plate: 46.5 mph at looks to be about 5700 rpms. The current prop is a Laser 2 25p. TIA.

Something seems off. Do you have a 1.87 gear ratio? If I use that ratio and your tach is accurate, it works out to 35% slip. It can't be that bad?? Either I am wrong using the 1.87 gear ratio, or your tach or speedometer is off. If all of them are really correct, including my assumption of a 1.87 gear ratio, you need to change the prop or whatever is causing the excessive slip.

Going to retest this week with my phone Gps. Thanks

**Jbone86** · 08-04-2021, 07:30 PM

Update*
My previous numbers were wrong, the tach was a little hazy on first run.

Laser 2 25p:
Hole shot: weak
Wot: 5100 rpms
Top speed: 47.5

Just tested new prop (still leaning towards a tempest)

Solas Hr3 19p (14.75d)
Hole shot: incredible
Wot: 6000rpms probably hitting limiter
Top speed: 50 mph

Only problem is that in fwd or reverse idle it stalls out with the larger diameter.

Leaning towards tempest just not sure on pitch yet. Any help much appreciated!

Thanks,
Jason

**Pulsare2400** · 08-04-2021, 10:37 PM

You still had 27% slip with the 25P Laser which still sounds too high unless the tach is out?? That H3 sounds much better, about 13% slip. I would imagine the hole shot is incredible moving from a 25P to a 19P and you picked up top speed as well. Good trial! What is the maximum rpm range the engine is rated for? A 21P HR3 would lower the rpm to about 5450 which might be too low. I would think that the engine stalling can easily be overcome by adjustments. The diameter might be a bit larger than a Laser but the pitch is way less so I would think the engine would be loaded less than with the Laser 2. I once had a 24P Solas Scorpion and it acted like a 26P prop. Not sure how the Solas H3 compares in pitch to the Tempest, perhaps some other member have at least compared the H3 to some other Mercury prop and then we could extrapolate better.

**Capt j** · 08-05-2021, 06:35 AM

Keep in mind the 1802 isn't known for being a fast hull compared to their 1890. The prop everyone loves is the tempest +, which is a 15.25" diameter. I'd try to get your hands on one. I have a 21" and am in South Florida (Pompano Beach), if you're anywhere near me you can try it. You'd need to buy a hub kit or use your own hub kit. Also Florida Sportsman forum has an entire section dedicated to Action Craft (near the bottom), there is a thread similar to yours there with the same boat and HP I believe.

**Jbone86** · 08-05-2021, 06:37 AM

Originally Posted by Pulsare2400

You still had 27% slip with the 25P Laser which still sounds too high unless the tach is out?? That H3 sounds much better, about 13% slip. I would imagine the hole shot is incredible moving from a 25P to a 19P and you picked up top speed as well. Good trial! What is the maximum rpm range the engine is rated for? A 21P HR3 would lower the rpm to about 5450 which might be too low. I would think that the engine stalling can easily be overcome by adjustments. The diameter might be a bit larger than a Laser but the pitch is way less so I would think the engine would be loaded less than with the Laser 2. I once had a 24P Solas Scorpion and it acted like a 26P prop. Not sure how the Solas H3 compares in pitch to the Tempest, perhaps some other member have at least compared the H3 to some other Mercury prop and then we could extrapolate better.

When I look online the max rpms are 5000-5500

**Jbone86** · 08-05-2021, 08:09 AM

Originally Posted by Capt j

Keep in mind the 1802 isn't known for being a fast hull compared to their 1890. The prop everyone loves is the tempest +, which is a 15.25" diameter. I'd try to get your hands on one. I have a 21" and am in South Florida (Pompano Beach), if you're anywhere near me you can try it. You'd need to buy a hub kit or use your own hub kit. Also Florida Sportsman forum has an entire section dedicated to Action Craft (near the bottom), there is a thread similar to yours there with the same boat and HP I believe.

Awesome, thanks for the offer but I'm near St. Pete on the gulf coast. I have heard the 1802 isn't as fast, I still want to get the best prop, 50mph is good with me but at 6000rpms might be to high? 5000-5600 is the max when I looked online.

**Pulsare2400** · 08-05-2021, 08:56 AM

Originally Posted by Jbone86

When I look online the max rpms are 5000-5500

IF that is the range then a 21P should put you in the range and possibly pick up a bit more speed.

**Jbone86** · 08-05-2021, 09:54 AM

Originally Posted by Pulsare2400

IF that is the range then a 21P should put you in the range and possibly pick up a bit more speed.

Awesome I'll go the 21p route then, how do I make adjustments to prevent the motor stalling at idle speeds? The motor idles in neutral at 900 rpms currently.

Thanks

**Pulsare2400** · 08-05-2021, 11:28 AM

If it was a carburator, I could help you. EFI, it might have to have the timing checked, fuel pressure, and perhaps other sensors. I would change the fuel filter for certain unless you already have done that. I am surprised it did not do it with the Laser 25P prop. To get around that for now, you could trim the engine so that the water intake is still below the water but some of the prop is above the water to reduce the load on the engine and then trim down after putting it in gear? Just a thought. Some other members may be able to help you more.

**Jbone86** · 08-05-2021, 11:55 AM

Maybe it's because I used a merc hub instead of a solas?

**Pulsare2400** · 08-05-2021, 12:35 PM

Perhaps, but I bought a 24p Solas Scorpion to test on my 2400 Pulsare / 300R and I also bought the Solas hub. It made a funny sound while running it, so I removed the Solas hub and used my Flo Torque Mercury hub. I could barely tell any difference when I put it in gear even though they said the Solas was supposedly smoother with less clunk. It was a bit less 'clunky" but only slightly. Of course totally different engine and brand new.