Help plz. 87 Mercury 150 xr2 Black Max

[Unkl L]

I just recently purchased a 87 hydra sport with 87 150 xr2 Black Max. Boat is real sluggish out the whole and will only run 5400 wot. It has a 23p prop. All cylinders have good compression. New stator was put on in March as I was told. Boat only runs 48mph and 5400 rpms. Everything I seen says should at least get 5800-6000 rpms easy.

[doroger]

Had an 89, I would sinc & link the carbs to make sure they are all opening and working correctly

Don

[Unkl L]

That's on agenda for Sunday. Also going to do waterpump housing and impeller. Just seems that I should be getting more rpms and more mph out the motor. It's on a 17ft hydra sport vs 150 t

[danover321]

Prop pitch is too high limiting your rpm range and hole shot. Your motor would do better with a 19-21 pitch prop.

[Unkl L]

What pitch prop are you running on your xr4

[danover321]

I was running a 22p Laser II which was limiting to my wot rpm to approximately 4900-5000. Reduced to a 20p and boosted rpm to 5400 at wot. I'm running the small gear case with 1.78 ratio.

[Unkl L]

I was running a 22p Laser II which was limiting to my wot rpm to approximately 4900-5000. Reduced to a 20p and boosted rpm to 5400 at wot. I'm running the small gear case with 1.78 ratio.

Did it also increase your mph?

[danover321]

I didn't loose any speed by reducing pitch. My rig tops out at 50-52 mph as it's no speed demon. What gear case are you running?

[OnTRAK]

A properly running 2.0 150 xr2 on that Hydra Sport hull should easily turn a true 23" pitch prop into the max 5500-6000rpm range for the xr2. When you do the sync & link, remove any idle/spark advance modules and set the max advance timing to 22*-23* BTDC. You also might want to put a rebuild kit in your fuel pump (it's easy) and make sure your fuel lines and primer bulb are the ethanol resistant type. Use only Mercury or Quick Silver replacement fuel lines and bulb. The aftermarket lines have been known to cause problems. The 2.0's don't generate a lot of low end torque, so you need to make sure your set up is right in order to get a good hole shot. I'm running a 1984 2.0 150hp Mariner (not a xr2/MagII) on a 1984 Dyna Trak 179 having a similar weight hull to your Hydra Sport and easily turn a 23 Tempest between 5800 - 6000 rpm without a jack plate. Your Hydra Sport has a faster hull design than my Dyna Trak.

[Unkl L]

I didn't loose any speed by reducing pitch. My rig tops out at 50-52 mph as it's no speed demon. What gear case are you running?

2.1

[Unkl L]

A properly running 2.0 150 xr2 on that Hydra Sport hull should easily turn a true 23" pitch prop into the max 5500-6000rpm range for the xr2. When you do the sync & link, remove any idle/spark advance modules and set the max advance timing to 22*-23* BTDC. You also might want to put a rebuild kit in your fuel pump (it's easy) and make sure your fuel lines and primer bulb are the ethanol resistant type. Use only Mercury or Quick Silver replacement fuel lines and bulb. The aftermarket lines have been known to cause problems. The 2.0's don't generate a lot of low end torque, so you need to make sure your set up is right in order to get a good hole shot. I'm running a 1984 2.0 150hp Mariner (not a xr2/MagII) on a 1984 Dyna Trak 179 having a similar weight hull to your Hydra Sport and easily turn a 23 Tempest between 5800 - 6000 rpm without a jack plate. Your Hydra Sport has a faster hull design than my Dyna Trak.

Thanks will do all that and let you know how she goes. I do have a manual Jack plate and started raising it a little. But had to go back down as prop was cavitating on launch.

[Jonestrollingmotor]

I know it's not apples to apples, but I had a 2.0 135hp merc on a 17' Basscat Caracal (heavier than the Hydrasport). 2:1 gear case on a 1989 model years. I could turn a 22 LaserII 5800 at a top speed in the lower 60's. That being said, when it would get to be a "Dog" out of the hole (happened twice) I found I had a bad switch box. Once out of the hole, it would cut my rpms down to around 5K. I agree with others, you should be able to turn a 22/23 on that motor/boat combination. As said above, I would also have the carbs cleaned and sync/link adjusted correctly.
John

[Unkl L]

I know it's not apples to apples, but I had a 2.0 135hp merc on a 17' Basscat Caracal (heavier than the Hydrasport). 2:1 gear case on a 1989 model years. I could turn a 22 LaserII 5800 at a top speed in the lower 60's. That being said, when it would get to be a "Dog" out of the hole (happened twice) I found I had a bad switch box. Once out of the hole, it would cut my rpms down to around 5K. I agree with others, you should be able to turn a 22/23 on that motor/boat combination. As said above, I would also have the carbs cleaned and sync/link adjusted correctly.
John

How did you test the switch box?

[FES313]

Have the timing checked by a mechanic that understands timing and timing advance. My experience with a xr2 150 sounds like yours. The stator went bad and I had it replaced. The parts changer didn't know squat about the timing(I didn't either).When I took it to another shop and explained the problem, the mechanic there said the timing was off and he would have fixed in just a few minutes. I took longer to write the check to pay him than it did to set the timing. I think the new mechanics rely on computers and readers that tell them what's wrong and don't understand how everything is supposed to work.

[Dubee]

I was running a 22p Laser II which was limiting to my wot rpm to approximately 4900-5000. Reduced to a 20p and boosted rpm to 5400 at wot. I'm running the small gear case with 1.78 ratio.

Sounds like you have motor issues if you can only turn a 20 5400

[paulrodbender]

I wonder if the 2.1 is the reason. I'm running a 24p 4 blade with a 88 XR4 - smaller 1.78 gearcase on a 374V and hitting 5600rpm

[PolarKraft195]

Do a shock treatment with seafoam!

[OnTRAK]

Have the timing checked by a mechanic that understands timing and timing advance. My experience with a xr2 150 sounds like yours. The stator went bad and I had it replaced. The parts changer didn't know squat about the timing(I didn't either).When I took it to another shop and explained the problem, the mechanic there said the timing was off and he would have fixed in just a few minutes. I took longer to write the check to pay him than it did to set the timing. I think the new mechanics rely on computers and readers that tell them what's wrong and don't understand how everything is supposed to work.

Good point. If doing it yourself, go step by step according to the Mercury factory service manual (#90-97658-3). You might also want to post this in the Mercury 2.0/2.4/2.5 & High Performance forum. Be sure to include your motor's serial # too. There is a lot of excellent help available there.

[danover321]

Sounds like you have motor issues if you can only turn a 20 5400

My motor runs just fine!

[Unkl L]

A properly running 2.0 150 xr2 on that Hydra Sport hull should easily turn a true 23" pitch prop into the max 5500-6000rpm range for the xr2. When you do the sync & link, remove any idle/spark advance modules and set the max advance timing to 22*-23* BTDC. You also might want to put a rebuild kit in your fuel pump (it's easy) and make sure your fuel lines and primer bulb are the ethanol resistant type. Use only Mercury or Quick Silver replacement fuel lines and bulb. The aftermarket lines have been known to cause problems. The 2.0's don't generate a lot of low end torque, so you need to make sure your set up is right in order to get a good hole shot. I'm running a 1984 2.0 150hp Mariner (not a xr2/MagII) on a 1984 Dyna Trak 179 having a similar weight hull to your Hydra Sport and easily turn a 23 Tempest between 5800 - 6000 rpm without a jack plate. Your Hydra Sport has a faster hull design than my Dyna Trak.

When you say remove any idle/spark advance. Are you saying permanently or just to get timing?