Need advice for getting boat on plane

[Jacobdemers73]

So I just bought a 1984 Lowe Lunker 3 16 foot fishing. Is a good size lake boat. Have a 5 gallon fuel tank 2 batteries trolling motor and usually at least 2 people a couple fishing poles and tackle. It’s got a 1984 Suzuki Dt 40 hp outboard with a 4 blade 10.8x12 prop. Decent compression on both cylinders. The boat struggles to get on plane. I have to mess with the trim a lot to get it to plane out. Any advice would be great. Not many resources on Suzuki outboards.

 

[Stinnett21]

Assuming you and your buddy sit in the back, two batteries in the back, gas tank in the back, etc. Guessing you badly need to move weight to the front somehow. 40 horse is not a lot for that rig. Take a look at Nauticus Smart Tabs.

 

[airshot]

Make sure your motor is running up to par!!! If not your wasting your time. I have a similiar 16' SC alum Sylvan boat. 15 gallon fuel tank in floor amidship, also 3 group 31 batteries at 80 lbs each and a marine starting battery. I have a Merc 40 hp 4 cylinder 2 stroke and my boat gets up on plane quite well using the power trim. My top speed is 31 plus with just me and fishing gear. My two group 31 batteries for the trolling motor are just forward of the side console, so.....move weight around and get a balance to help you get up on plane. Your passenger may not like his seat position but you gotta do what is necessary to get your boat balanced...

 

[racerone]

That motor should have no trouble with the boat.-----Post your compression values.-----" decent " compression means nothing.----Test to see if there is spark on all leads.

 

[harringtondav]

Knowledgeable replies above point to low power. Weight distribution will help. Also the boat could have waterlogged flotation foam. Weigh your boat, trailer, tow vehicle, launch the boat and weigh again for the boat's weight. Compare this to the dry weight spec, minus fuel, batteries and gear.
As is, a lower pitched prop could speed up planing, but it will cost you top speed.

 

[Texasmark]

Knowing your wide open speed and engine RPMs would help us to understand the problem. In looking at the position of the helm, with your essentials and the side by seat positioned where it is, I too think you are stern heavy and 40 doesn't have enough whoopie to get you up all that fast.

Not much you can move forward with side by side seating. Assuming the engine is up to par, as mentioned, stern lifting aids, including a Whale's Tail type mechanism that bolts to the antiventilation plate on the engine should be an asset. Folks have mixed emotions about the WT type device but on your boat/engine combination,

I think one would be an asset and not have any ill effects encountered with some different item specific boats...boats with high HP engines that run at reasonably high speeds...problem is at speed, not getting up.

 

[racerone]

Buddy bought a 16' aluminum with a 40 HP--------------No issues getting up on plane at all !!
''

 

[QBhoy]

Send us a wee picture looking at the stern and engine set up.

 

[jimmbo]

So I just bought a 1984 Lowe Lunker 3 16 foot fishing. Is a good size lake boat. Have a 5 gallon fuel tank 2 batteries trolling motor and usually at least 2 people a couple fishing poles and tackle. It’s got a 1984 Suzuki Dt 40 hp outboard with a 4 blade 10.8x12 prop. Decent compression on both cylinders. The boat struggles to get on plane. I have to mess with the trim a lot to get it to plane out. Any advice would be great. Not many resources on Suzuki outboards.

Welcome to iboats

I am curious as to what Rpms you are getting at WOT.
My thoughts... That forth blade is loading the engine up too much at low rpm, hence the poor Hole Shot.
Things that are easy to check:
As already mentioned, Compression
Are all Cylinders getting a Spark that can jump a 7/16" gap?