jackplate adjustment

[rattletrap201]

i had a 4 inch jack plate put on my boat, i took it out and ran it today did good out of the hole throug mid range lost 1 or 2 mph on topend, how do you tell if you should go up or down? it was also show more waterpressure running a jack plate than with out, so can to much hurt? the setup is a 96 stratos 201 with a 96 200 johnson 24p raker showing on the jack plate it is rasied 1.5 in it probly raised 2.5 from where it was on the transom just wonderin should i go up or down. 65.8 on the gps had it to 67 before. thanks

 

[stratos21xl]

Most Stratos hulls like anywhere from 2 1/2 to as much as 4 inches below the pad of the boat and that's measuring from the center of the prop shaft. What RPM's where you turning at WOT before the jackplate and what are you turning now? Dialing in a boat is trial and error at best. Are you saying it has been raised a total of 4 inches? If so I would definitely start by going down first.

 

[rattletrap201]

it probly rasied 3 1/2 total right now before it would turn between 5600-5700 today it did about 5500. and the water pressure was never above 25 or so but today it was above 30 i was thinkin it was to high but also thought if it was to high i would lose pressure and gain rpms. but it was great out of the hole and midrange

 

[stratos21xl]

if you lost RPM's and gained water pressure then it's probably to low. Try to go up one notch and run it and see what kind of numbers you get. You are close now as far as RPM's and one notch higher should get you there. Adding a jack plate may also affect the trim angle so it may take less or more trim to get lift. You might want to play around with that too before raising or lowering the motor.

 

[Fishingron]

Ditto what stratos21xl said.