BillR has them in his Top Gun which he recently purchased with about the same number of hours. He loves his engines and they have not missed a beat.

Merc deliberately goes easy on the engines keeping the boost low for reliability. The easiest performance upgrade is to install a whipple intercooler under the blowerw and voila you have another 25 to 40 hp. The whipple intercooler is the same height as the stock intake manifold.

they are great engines!

 

Suppose to be a great engine. Heard a lot of positives. No real negatives. Only thing is, Merc. discontinued them becuase the 525EFI puts out around 540HP where as the 575SCI put out 550HP and the 525EFI was of course fuel injected and closed cooling.

 

Ya but.... the COOL factor goes to the 575's :vcol:

 

Ya but.... the COOL factor goes to the 575's :vcol:

Ya mean you don't like the look of an EFI motor? LOL.

 

If its a salt water boat, pull the thermostat housing hoses and look for corrosion. I have seen them corroded almost closed in under 100 hours.

 

how could those look bad?

I do love the EFI's I have 2..... but being old...
blowers take me back.....

 

so what's a little maintenace on your baby....go for the blowers...

talk about disappointed - karen and I were at Ocean Performance few weeks ago looking at Cigs and OL's and they had a 42 OL in the showroom with triple HP 525 EFI's - yes, they're sweet but in a boat like that I want to see BLOWER MOTORS!!!!!!!!

 

Yes they are awesome! They will use about 10% more fuel.
The thing to look for is to make sure the seals on the blower pulley's are not leaking oil. Early models had issues with bad seals. Check the repair history, it is likely that they have been replaced. Also have compression and leakdown test done.

So far they appear to be a rock solid turn key motor. Only extra maintenance is to change blower oil about every 50 - 100 hours. "I" plan to change oil around 25 hours as they do run rich.

Once you run these, you'll be hooked. I was VERY skeptical about blower motors, but since this is a very mild Merc engineered package; I am now comfortable.

Also, Scott Buteyn of Mercury Racing was here checking out Nauti-Props boat and doing some field testing. I got to spend quite a few hours talking with Scott about the 575 (and others) and any issues that Merc may have experienced with it. Basically it is a VERY sound motor. Scott said that head gaskets should be replaced about every two years and "check" valve springs about 300 - 400 hours.

Go for it, you'll be glad you did.

 

Yes they are awesome! They will use about 10% more fuel.
The thing to look for is to make sure the seals on the blower pulley's are not leaking oil. Early models had issues with bad seals. Check the repair history, it is likely that they have been replaced. Also have compression and leakdown test done.

So far they appear to be a rock solid turn key motor. Only extra maintenance is to change blower oil about every 50 - 100 hours. "I" plan to change oil around 25 hours as they do run rich.

Once you run these, you'll be hooked. I was VERY skeptical about blower motors, but since this is a very mild Merc engineered package; I am now comfortable.

Also, Scott Buteyn of Mercury Racing was here checking out Nauti-Props boat and doing some field testing. I got to spend quite a few hours talking with Scott about the 575 (and others) and any issues that Merc may have experienced with it. Basically it is a VERY sound motor. Scott said that head gaskets should be replaced about every two years and "check" valve springs about 300 - 400 hours.

Go for it, you'll be glad you did.

Bill,

How much boost do they put out, and at what RPM do your motors idle at?

 

Mine idles at 800-no load up at all. Almost a perfectly clean transom.

 

BillR has them in his Top Gun which he recently purchased with about the same number of hours. He loves his engines and they have not missed a beat.

Merc deliberately goes easy on the engines keeping the boost low for reliability. The easiest performance upgrade is to install a whipple intercooler under the blowerw and voila you have another 25 to 40 hp. The whipple intercooler is the same height as the stock intake manifold.

they are great engines!

Adding a cooler will not make more hp. It will allow you to up the boost to make more hp safer, as it cools the intake air that is now hotter after being compressed to gain more boost reducing the fear of detonation. The whipple cooler is not very high, which should install w/o having to raise your engine hatch.

 

Gilla: I guess it allows you to take better advantage of the hp you have huh? Sounds about right.

 

Adding a cooler will not make more hp. It will allow you to up the boost to make more hp safer, as it cools the intake air that is now hotter after being compressed to gain more boost reducing the fear of detonation. The whipple cooler is not very high, which should install w/o having to raise your engine hatch.

OK this contradicts what Speedwake said...who is correct? OR both are?

 

I am-without a doubt.

The more boost the more heat generated by the blower and higher induction air temps. It can get so hot entering the cyl that it will detonate-like a diesel-before the spark plug fires. This is your major engine damge.

Also, we know that cooler air is more dense than hot air, therefore-you can pack more air in the cyl if it is cool-getting more power if you have the correct fuel ratio.

With no other changes to a blower motor that is being correctly fueled and cooled-the addition of a chiller will not make more power. It will allow your engine to make the same amount of power it currently does, over a longer wot run. This is because you engine at wot slowly makes more heat-heating the intake and the blower is also generating more heat, causing a loss in hp. The chiller maintains your original power over a long wot run.

Now add the chiller and you can up the boost, add the needed more fuel and a timing change and you can get the hp increase we all desire. :bigsmile:

 

Bill,

How much boost do they put out, and at what RPM do your motors idle at?

4.5 lbs
Idle at 750. Very smooth operation. EFI!!!!!

 

Very Interesting!


How do you think my 22' would perform with a 575SCi?


Now that would be fun ride....till you hit the first ripple in the water... me thinks I would need a 3-4 ft tab :smile1:

 

4.5 lbs
Idle at 750. Very smooth operation. EFI!!!!!

Smooth enough to run 90mph in 5 foot swells? YEAP>...we all saw it...

 

4.5 lbs
Idle at 750. Very smooth operation. EFI!!!!!

BillR,

Is it the stock pulley on your blower? It is suppose to be around 3.5 lbs of boost.

My EFI too idles smooth at about 750.

 

Hey BillR - I've got some really cool small pulleys that'll get that bad boy up to about 12 lbs of boost - you'll see 100 mph for a few seconds then you'll send one of the heads flying through the engine hatch....

should be a heckuva sight

 

Now that would not be cool! Na ah... :rambo:

 

I have the stock Merc pulleys and plan to keep it that way. The boat is fast enough. (did I just say that? )

 

Yes you did - and get this - your right!

 

I have the stock Merc pulleys and plan to keep it that way. The boat is fast enough. (did I just say that? )

I am happy with mine stock as well. For now.

 

Bill-I don't think you have stock ones at this time. Mine also runs 3.5 lbs. I think someone has already given yours a little boost.

 

uh oh - are you not telling us everything Bill ? Do you have a 50 shot of NOS also to get the big thing over 90mph?