Raising 175 EFI on the adjustment holes...

[Sam I am]

Thanks to everyone for chiming in...here's what happened. I took it out this morning and trimmed it all the way down for the hole shot. I eased iinto the throttle and had a lot of cavitation. However, it did plane out. I kept a close eye on the discharge and moved toward WOT. Going wide open and watching the discharge is a lot easier said than done. I was trimmed up and flying, very stable, no more water at discharge, and then a horn went off. RPMs were 6000...I was already out of the throttle when I looked at the speedo dropping through 59. Trimmed back down, discharge resumed and tried another hole shot. Bad cavitation. So, it's now too high.

Pulled the boat out of the water, back to the hoist, and lowered the motor to the middle adjustment hole. Back into the water, and the hole shot was fine, no cavitation, discharge solid, wide WOT no problem and very stable. I then trimmed the motor up and the bow came up, the speed picked up, the revs went to 6000 and she got loose again, but this time it was controllable and didn't scare me into backing out of the trottle. But the horn went off again.

So, is the horn for revs or water pressure? I'm thinking revs...in which case I will have to go to a 23P prop rather than 21P. This is kind of fun, but a hyro jack plate will be going on before next season.

Oh yeah, went to the local mercury dealer looking for the scoops and they had no idea what I was talking about. They couldn't find them in the parts book either. If anyone has a part number I would really appreciate it. Thanks.

Sam I am

 

[Rob B]

Scoops

Here you go, this is from my post for setting up the Pulse 170

Today I purchase the scoops from a Mercury Dealer. They actually had them in stock. For those that are interested in the scoops, they're called "High Speed Water Pickup" part #17280A2. I'm hoping to install them tomorrow. Now that i've added water temp and pressure gauges, water pump, thermostats and a jack plate hopefully i can get a few runs this weekend and play w/ the setup. Here's what they look like not installed.
Attached Thumbnails

 

[Mark]

I then trimmed the motor up and the bow came up, the speed picked up, the revs went to 6000 and she got loose again, but this time it was controllable and didn't scare me into backing out of the trottle. But the horn went off again.

So, is the horn for revs or water pressure?

If it is a steady beep it is your overheat alarm. You don't ever want to hear that alarm. You can destroy a motor in mere moments. Don't even run the motor that high till you get the scoops.
You really need to put in a water pressure gauge. They are only $30 and then you know long before the motor starts to overheat that you are not getting enough water.

 

[Reed]

I can't lift a V6, but I can do a V4. I am a pretty big guy, 6 ft 240, but it takes me an my buddy to do the V6. I did a V6 powerhead only does that count?

Hmm, need a hand with the Merc again ?? Hey Shane, I will be on the water Labor Day Weekend I think Sat. ( Just finished putting the power head back together, re-packing wheel bearings and new rims/tires, All that is left is charging the battery, and re-wiring the new trailer) *Those V-6's are a lil heavy I have lifted one by myself about 10 yrs ago *

 

[hotdaddy27]

Which "beep" was it?

 

[Sam I am]

The beep was...

...steady tone. So, if what i read was right, it was the overheat alarm. Like I said, I was alreadyout of the throttle and the horn went almost as soon as I did that.

I took it back out tonight and had no horn, no problems, but I kept the motor trimmed quite low. I was able to get to wide open, but I can tell there is still a lot of bow in the water. When I trim it up, it really jumps forward, revs get higher and she really starts to howl. It actually sounds awesome. I slowed down trimmed up a ways and put it down for about 5 seconds and the rooster was specatular.

Next step: scoops and H2O gauges. Maybe a jack plate this winter.

 

[Mark]

Sam
Kinda playing with fire. You could also cook your impeller if it is not getting water. At 6000 RPM an impeller would melt in 5 seconds. Chances are there is enough water in there to lubricate it but I would check the impeller when you install the scoops. You can install them w/o pulling the LU but it is easier with it off and I highly recommend you check that pump.
Not being a smart alex...just trying to help.

 

[Sam I am]

Yeah...you're right of course. Will the scoops elminate the H2O intake problem or do they only help? If they don't fix it, then I may just lower it back to the bottom holes and live with the instability. At least it won't burn up.

Stupid question: I thought transoms were designed to an industry standard, or at least a ball park standard. So, if that's true, why make a motor with adjustment holes that can't be used...or is this a problem unique to my hull?

 

[Rob B]

Yeah...you're right of course. Will the scoops elminate the H2O intake problem or do they only help? If they don't fix it, then I may just lower it back to the bottom holes and live with the instability. At least it won't burn up.

Stupid question: I thought transoms were designed to an industry standard, or at least a ball park standard. So, if that's true, why make a motor with adjustment holes that can't be used...or is this a problem unique to my hull?

Sam when I added my scoops, the water pressure went up, so I had the ability to raise my engine w/o it over heating. Also if you add a jack plate and different prop you wouldn't need to over trim to get the bow up. Look at my post on setting the pulse 170 up, all the details are there.

 

[JW]

There sort-of IS an industry standard for transoms, but not how you think of it.

Checkmate, being a slightly more 'performance' oriented brand of family boat manufacturer, has always made it's transoms a tad taller so your motor already ran a bit higher than 'other' family boat manufacturers.

The Four Winns I owned in comparison had a transom cut so short, that I had to lift the motor ALL the way to the very lowest holes on my outboard for the LU to be at a 'normal' buried level. From the factory, the Four Winns was buried so deep at the top holes that my outboard was WAY too deep. Four Winns does that so you couldn't lose prop bite or water pressure no matter how high you trimmed.....................

So where I had to move my outboard on the Four Winns to the very lowest holes to get the propshaft 4-5" below the bottom of the boat, you do that on a Checkmate and you're way too high for a normal lower unit water pickup.

 

[Mark]

Yeah...you're right of course. Will the scoops elminate the H2O intake problem or do they only help? If they don't fix it, then I may just lower it back to the bottom holes and live with the instability. At least it won't burn up.

Stupid question: I thought transoms were designed to an industry standard, or at least a ball park standard. So, if that's true, why make a motor with adjustment holes that can't be used...or is this a problem unique to my hull?

The standard transom is 20". Checkmates are 22" so your starting point is already 2" higher.

 

[rowdy1]

Lets get back to hanging outboards without a hoist! I got a cooler full of cold ones for the guy that can bear-hug my 300 V8, on or off!

 

[Sam I am]

Update...

...but no pics.

OK, I got the H2O Pressure gauge and the H20 Temp gauge put in this last week. The shop called and told the temp gauge is a no go right now because of a bad sender. New one coming soon. But I needed the boat this weekend for guests so I took it knowing I'll be bringing it later this week.

The P gauge reads about 7 at idle and goes to 15 at WOT trimmed up. Never heard the overheat horn. The stability was better but still not great. But I could drive through the oscillation at WOT. Maybe I'm just getting better at driving.

I never got a magic pressure number out of the shop for minimum pressure. anybody want to enlighten me?

I also installed the scoop kit. Not too hard and must be helping since I never heard the horn. The shop confirmed that was the overheat alarm I heard and checked it to see when it would come on. It's set to go off at 180. I''m assuming F not C. They claimed that was pretty conservative and said as long as I didn't drive it for an extended time with that horn going off, than I don't have anything to worry about.

The boat picked up 4 mph to an indicated 65 according to the dash speedo while revs at WOT were 5800. It was a lot of fun!

Thanks for everyone's help in this matter and enjoy your winter.

Sam I am

 

[Mark]

That's good news that you probably did not overheat the motor. You are not likely to run out of water now with the scoops. They really work well. 15 psi is perfect, 12 would be the minimum at WOT.

 

[hotdaddy27]

Congrats..

Good to hear that you are getting things worked out!

Now you can raise the motor slowly and keep an eye on the pressure as you go. I never ran the scoops, but I have only heard positive reviews about them.