Throttle adjustment question

[panasonic]

Sounded like it was wide open, if not very near to it. I have been running my father's 40 HP 1991Mariner for years. It has outlasted two 19' foot wooden fishing boats and now it's on a 19' fiberglass open fishing boat. Last summer I had it doing 28 mph, GPS, with two small people aboard. It must be a 15' boat if it will go 36!

Glad you got it sorted out. A 5 gallon bucket of water with a good lid up fwd will help keep her from dancing around to much as Jason said....Be safe.

[Mn carguy]

Enjoyed the video. Son of a gun was gettin' squirrelly at the end

Well, as a former owner of 2 yam small block 2 strokes it does sound like you're winded out to WOT. I hear this around the 25sec and 1min marks of the video. I do find it highly unlikely the rpms are only 3800, strictly because the engine pitch would be lower.

I also find it very unlikely the boat topped 36mph, even if I hadn't watched the video. I can't tell if your dauntless whaler is the 15' or 18' model. The 15' model dry weight is just under a 1000lb, your engine just under 200lbs. Add your weight plus fuel weight and your total weight is around 1350lbs. I just seriously doubt a 40hp engine is going to push 1350lbs 36mph. If your whaler is the 18' model, I'm positive the 40hp will not push a 1 ton boat over 30mph.

While the boat was experiencing instability (porpoising) were you trimmed down? I didn't see you make a trim down adjustment during this time to counter the porpoise effect. I ask because if you move the engine up one more notch this will only add to the instability. Assuming your boat is the 15' model, small boats like this are tremendously affected by the weight in the boat and where the weight is located. Luckily you have PT/T to help with this.

When I had a 15' fiber hull like yours with a 25hp 2s, I'd keep a cinder block in the boat that I broke in half. If I needed some weight up front, up would go the 1/2 or full block inside the compartment. Need weight in the rear, port, starboard, etc. Just move the blocks around. Thank goodness I no longer have to do that anymore. Though I did become an expert with small boat weight distribution, so theres something.

It's a 13 footer. The gps is a cell phone app that I've used for years and it matches my car speedos so I think it's pretty accurate. The boat porposed more on the initial run with the motor in the bottom hole and just a touch of trim. I could have trimmed down but I had one on the wheel and the other on the phone. I agree completely about the rpm and one of the reasons I shot the video was in hopes a yami owned would agree with the idea that it 'sounded' about wide open. Someone else mentioned safety and I was actually wearing a life jacket and had the lanyard on (something I rarely do to be honest).

Thanks to everyone for the ideas and input.

[TownsendsFJR1300]

Yep, agreed, it's spinning quite a bit over 3,800 RPM, much closer to 5K I'd guess...

Great running engine and clean rig too!

[Jason2tpa]

It's a 13 footer. The gps is a cell phone app that I've used for years and it matches my car speedos so I think it's pretty accurate. The boat porposed more on the initial run with the motor in the bottom hole and just a touch of trim. I could have trimmed down but I had one on the wheel and the other on the phone. I agree completely about the rpm and one of the reasons I shot the video was in hopes a yami owned would agree with the idea that it 'sounded' about wide open. Someone else mentioned safety and I was actually wearing a life jacket and had the lanyard on (something I rarely do to be honest).

Thanks to everyone for the ideas and input.

Aah, the 13 footer. Now I know the length I change my previous statement about the mph accuracy. I can definitely believe a 13' with 40hp can top in the high 30'smph. And as a former operator of small boats like you have I absolutely advise to always wear the lanyard. I never wear a life jacket, so I made a velcro wrist band with a circular key ring. The lanyard clipped to the ring.

[99yam40]

people that get thrown out of boats at high speeds usually drown when knocked unconscious if they do nor have something to hold their head above water even if the boat motor dies from pulling the kill switch.

At least the rig will not circle around and run over the body if kill switch it pulled.

I normally run about 25 mph , faster if running from a storm. if alone I will wear the kill, but never have wore a life jacket either.
Shame on us.
Guess we need to get some of those auto inflate ones and wear all of the time on the boat

[Jason2tpa]

people that get thrown out of boats at high speeds usually drown when knocked unconscious if they do nor have something to hold their head above water even if the boat motor dies from pulling the kill switch.

At least the rig will not circle around and run over the body if kill switch it pulled.

I normally run about 25 mph , faster if running from a storm. if alone I will wear the kill, but never have wore a life jacket either.
Shame on us.
Guess we need to get some of those auto inflate ones and wear all of the time on the boat

You ever barefoot behind a boat? Pulling an average size man boat speed is gonna be lowest round 30mph. Heavier the tow, faster the boat speed needs to be. You'd be surprised the head bashing you can endure at 30mph and still be conscious. Though I don't recommend doing it for fun....headache for days

[throrope]

Back to the cables - If you feel like you have too much resistance on the lever, I suggest replacing the throttle and control cables. IMHO they are 20 minute maintenance items and can be easily delivered to your front door from this site and many online retailers.