Intruder 150

[97 hydrasport]

I had part of this posted in the motor section and thought i needed to ask here. I have a '97 LS 175 Hydrasport with the intruder 150. Right now the centerline of the prop shaft is 6-3/8" below the lowest point of the hull at the transom. The prop that came on the boat is a raker 14-1/4" x 24. Top speed so far has been 61(gps)@5200 it starts to chine at that speed and you can't get all of the trim out before it start to walk. I'm not looking to be a speed demon just feel like there is a lot of performance that I'm not getting. On a jackplate how much setback and what is a good brand and is a hydraulic/electric worth the price difference than a manual model? I know there is something that I should be telling you so let me know any more info that you need. Thanks for any help.

 

[walleyehed]

Re: Intruder 150

I assume you don't have a plate now with the distance from hull to prop-shaft that you list.
I'd take a look at the Bob's Machine model 1955, 8" hydro.
I don't think you have a bad prop choice there...it's just not running high enough. If you can get the engine back and up, I think you'll be able to "drive through" the chine-walk. Your target RPM for that engine with a normal load is 6000rpm. If it works out at 5800, that'll have to do, but I wouldn't want any less, and I think if you can reduce the gearcase in the water and get that Raker up some, you should see better over-all lift with less wetted surface...so I think the 5800 is well with-in reach.
If you don't already have a water pressure gauge, I'd highly recommend it with a plate.

 

[97 hydrasport]

Re: Intruder 150

You say that 5800 to 6000 rpm's is the best for the motor and the book says that 5500 should be the max. Does turning more rpm's hurt the engine and does cruising around at 4000 to 4500 hurt the motor? I was also wondering what would be a good place to start for the prop shaft below the hull with the jackplate? I do have a water pressure guage and know to watch it because she's not going to live long without coolant flowing. Thanks for your help.

 

[walleyehed]

Re: Intruder 150

Yes, the book says 5500, but consider the year it was built and the quality of fuel we had then...our fuel sucks at best now and for several years we've been bumping up the RPM to keep the coking and carbon build-up, down. If you want any life out of that engine, 5800 is the minimum...I run my 200 crossflow at 6250-6500 and have for over 600hrs now. It's max recommended is 5750..the crossflow do well at 5800...the Loopers do best at 6000, "then" your cruise at 4000rpm will be very efficient.
As for hurting the engine...No, it's just an airpump(copyright-Dhadley).....that engine don't know it's turning 6000...it's on needle bearings, and it actually has less stress at 6K than it does at 5500.