Houston Maverick Posted November 17, 2020 Report Share Posted November 17, 2020 I have read a lot about the need for a Jack Plate. I have a 1990 with a 2019 Yamaha 115 SHO and a 2" Jack Plate. I have the jack plate on the lowest setting and no matter how I trim and tilt the motor I can't get on plane. I have seen Mav's with Jack Plates and I'm trying to understand what I am doing wrong. I can get up on plan after some time and speed. Meanwhile It feels like a tractor pull and then when I get the front down the boat will start bouncing. Please help. Any advice would be great. Quote Link to comment Share on other sites More sharing options...
Lap it Up Posted November 18, 2020 Report Share Posted November 18, 2020 Post some pics of where the engine is mounted on the plate. Also post pics and numbers of your prop. This will help greatly. Quote Link to comment Share on other sites More sharing options...
whichwaysup Posted November 18, 2020 Report Share Posted November 18, 2020 Something is definitely off. a 115 should be plenty to jump that boat up on plane. I think the 1990 hull is the lighter version (is the front deck recessed or flat across?). Quote Link to comment Share on other sites More sharing options...
Wanaflatsfish Posted November 18, 2020 Report Share Posted November 18, 2020 5 hours ago, Lap it Up said: Post some pics of where the engine is mounted on the plate. Also post pics and numbers of your prop. This will help greatly. Are you using trim tabs? dc Quote Link to comment Share on other sites More sharing options...
whichwaysup Posted November 18, 2020 Report Share Posted November 18, 2020 10 minutes ago, Wanaflatsfish said: Are you using trim tabs? dc My 87 had a tired 115 2 stroke and no trim tabs. Never had a problem jumping on plane. Quote Link to comment Share on other sites More sharing options...
Houston Maverick Posted November 24, 2020 Author Report Share Posted November 24, 2020 Here are some photos. The front deck is recessed above the tank. I have trim tabs but the pump doesn't work so they are in the up position which is flat with the bottom of the boat. I have the jack plate attached to the lowest setting and motor mounted on the lowest hole for the plate to motor connection. What gets me is that when I throttle to go the back of the boat drops and its like a tractor pull. Quote Link to comment Share on other sites More sharing options...
wthree3 Posted November 24, 2020 Report Share Posted November 24, 2020 Simplest answer is fix the trim tabs and you will solve the holeshot and porpoising problem. Quote Link to comment Share on other sites More sharing options...
Wanaflatsfish Posted November 24, 2020 Report Share Posted November 24, 2020 4 hours ago, Houston Maverick said: I have trim tabs but the pump doesn't work so they are in the up position which is flat with the bottom of the boat 100% your problem for sure.....the MA's are very sensitive to weight and tabs. Forget the pump and just buy a set of Bennet Electrics...they are nearly plug and play.....I changed mine in about 2 hours. The holes fit directly into the same holes and they are super fast. dc Quote Link to comment Share on other sites More sharing options...
jim33042 Posted November 25, 2020 Report Share Posted November 25, 2020 Call the maker of the pump, they use to warranty them for life. I sent a few bad pumps over the years to Bennett and they always sent me a new one. That is if it is bad - you may want to check the dash switches as I have had those go bad as well. Quote Link to comment Share on other sites More sharing options...
Toeknee217 Posted November 25, 2020 Report Share Posted November 25, 2020 I don't have this hull but it looks to me (Cant tell too well from the photo) like the engine could be mounted too high on transom. At least on my Hewes, (which also has a transom pocket) my anti-ventilation plate is about equal with the flat portion of the transom pocket and not the v of the hull. The boat really needs me to trim the engine all the way down to come out onto plane or it'll porpoise like you mention. Hopefully someone with your hull can confirm where their anti vent plate is in reference to the transom to eliminate that as your possible problem. Quote Link to comment Share on other sites More sharing options...
Lap it Up Posted November 30, 2020 Report Share Posted November 30, 2020 On 11/24/2020 at 7:50 PM, Toeknee217 said: I don't have this hull but it looks to me (Cant tell too well from the photo) like the engine could be mounted too high on transom. At least on my Hewes, (which also has a transom pocket) my anti-ventilation plate is about equal with the flat portion of the transom pocket and not the v of the hull. The boat really needs me to trim the engine all the way down to come out onto plane or it'll porpoise like you mention. Hopefully someone with your hull can confirm where their anti vent plate is in reference to the transom to eliminate that as your possible problem. I agree. Hard to tell from those pics but it does appear too high. Quote Link to comment Share on other sites More sharing options...
HoneyB Posted November 30, 2020 Report Share Posted November 30, 2020 Your motor looks high to be all the way down. But it also looks like the jack plate is mounted in the top hole as well as the engine. I do not see how you could lower it with that jackplate short of drilling the boat again and I’m sure you do not want to do that. Quote Link to comment Share on other sites More sharing options...
polliwog Posted January 28, 2021 Report Share Posted January 28, 2021 Are you getting a lot of prop spin blow out when you hit the throttle? As others have said It appears the motor is at least a few inches too high. The anti cavitation plate should be at the same level as the hull's lowest level. I have a 20ft LT and it is set that way and I never have to use tabs to get up on a plane. I realized they are different hulls,but the concept is still the same. Quote Link to comment Share on other sites More sharing options...
whichwaysup Posted January 28, 2021 Report Share Posted January 28, 2021 This is an old thread, so curious if the OP is still out there and if there is any update. Trim tabs are a bandaid here. You shouldn't need them to simply get on plane. Yes, they should help you get on plane flatter and faster, but if you need them to get on plane at all, something bigger needs to be addressed. OP: let us know if you are still dealing with this problem. Quote Link to comment Share on other sites More sharing options...
polliwog Posted February 2, 2021 Report Share Posted February 2, 2021 Houston,we have a problem, LOL Quote Link to comment Share on other sites More sharing options...
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