2020 25hp Tohatsu dealer says....not!

[Mechmagcn]

Hi folks! I had posted that I thought this motor was running on 2 out of 3 cyls. dealer says it's running on all 3.
A little history, a few weeks back I ran out of gas on one tank and switched to the other. After doing so the motor would almost plane the boat and then act like it was starving for gas. I replaced the water separator filter and checked the screen on the motor, both had little water in them. Talked to my dealer and he suggested changing the spark plugs, this helped a little, but it still had no power and wouldn't plane the boat. Took it in to the dealer because it's under warranty. Tech says the fuel system is full of water and debris, I know better because I just checked the screen and there was absolutely no debris there. Of course this wasn't covered by warranty, so $300 later I'm back in the water.
Still no power and won't plane so I took it back. Tech says they scanned it, 55.3hrs., 42PSI fuel pressure, and no codes. Ran it on muffs, even put it in the water. They say there's nothing wrong. They even had tech support online with the scanner hooked up.
I'm sorry, but the day this started it would push the boat 24MPH with 2 people in it, now it struggles to get 15 and won't plane. The dealer tried to say the boat is waterlogged, I agree it is, but it's been in the water for 8 years and is no heavier than it was 18 months ago when this motor was installed.
I'm out of options here, hopefully someone here can give me some insight on what is going on, my dealer has given up. Cooler weather is on the way and this is our daily transportation.
Here's the boat before the new Tohatsu.

 

[pvanv]

What is your WOT RPM? Is the oil even a drop over full? Have you checked for a spun prop? Check all that first.

 

[Sea Rider]

Yep, if the motor revs strong throughout the whole throttle range check if having a hub on its way to become fully spun or already shot. Was the motor delivered with a 10 pitch prop ? if so it's a medium pitch one not suited for heavier applications as yours. Will need to install an induction tach to check wot revs as usually loaded to know how far the motor is revving from ideal middle to max wot rpm range factory stated.

Happy Boating​

 

[Mechmagcn]

Prop isn't spun, the motor never comes close to max rpms. Before when you got the boat on plane you could trim the motor slightly until it would cavitate and the overspeed alarm would sound. Now you have to trim up till it almost stops pulling before the alarm will sound, that tells me it is down on power.
I'm not sure what all the tech did, said he killed out each coil and each injector, but didn't say if that was done under a load. It seems like there is little throttle response over half throttle and it picks up a vibration. That's why I say it's dropping a cylinder under a load.

 

[Mechmagcn]

Pulled the boat back out of the water , checked oil level, right on the full mark with motor level. Pulled the plugs, still white with a slight haze. Decided to put the old ones back in, motor would idle smooth, but when throttled up it would cut out and sometimes backfire. At times it would run on 2 cylinders and then cut down to 1.
I put the new plugs back in one at a time and all three made improvement. Even swapped a new one from hole to hole to see if one of the new plugs was bad. All plugs are equal in color. Here's a pic of the old plugs and one of the new ones.

 

[Mechmagcn]

Is the oil even a drop over full?

Not sure what difference this would make, but oil level is on the full mark with motor level. Please explain?

 

[Mechmagcn]

Was the motor delivered with a 10 pitch prop ? if so it's a medium pitch one not suited for heavier applications as yours. Will need to install an induction tach

Happy Boating​

Yes, the motor was delivered with a 10 pitch prop. Until this started it ran right below the max rpms, so it's not overpropped.
Induction tach, I've tried three different ones and have yet to find one that will work on this motor.

 

[Mechmagcn]

Oh, by the way, I'm not new to boats or outboards, just the newer 4-strokes and fuel injection. We live on a river in south Arkansas and our boats are daily transportation. I bought this motor hoping to not have to work on it weekly like I was doing the 30y/o Johnson it replaced.
My experience has mostly been diesel as I am a retired truck and heavy equipment mechanic.

 

[racerone]

Flush the fuel system.---Clean injectors.----Replace filters.------Inspect fuel pump.-----Monitor fuel pressure.------How did a 1 year old fuel tank end up with " debris and water " in it.-------Or did you not get a new tank with this new motor ??

 

[Mechmagcn]

Flush the fuel system.---Clean injectors.----Replace filters.------Inspect fuel pump.-----Monitor fuel pressure.------How did a 1 year old fuel tank end up with " debris and water " in it.-------Or did you not get a new tank with this new motor ??

Entire fuel system has been cleaned and flushed by dealer, plus 2 new tanks is what cost me $300.
Not sure how debris made it past a 10 micron water separator and the screen on the motor, but that was the dealers excuse. Now he says "he's done all he can do".
I'm trying to get stuff together to check the fuel pressure, almost positive the dealer had no way too monitor under a load. If the laptop doesn't tell them what to replace, they are lost.

 

[Sea Rider]

Yes, the motor was delivered with a 10 pitch prop. Until this started it ran right below the max rpms, so it's not overpropped. Induction tach, I've tried three different ones and have yet to find one that will work on this motor.

Some issues :

How do you know said motor with a 10 pitch prop ran right below the max wot rpm range which is 6 K. Have never seen an OEM prop over revving way over max rpm range, not even powering light alum open boats much lighter than yours at full throttle.

If you have not checked the max wot rpm achieved with any other non induction tach as loaded won't ever know at which wot rpm the motor was reving before having tech issues. Surely revving towards the extreme lugging side under 5 K which it's extremely bad for the motor. Tohatsu plays extremely safe on their side with motors factory delivered with a prop, which in most cases are only good for break in purposes, right after need to prop right your current application with less pitch props.

Is that a manual or electric trim, tiller driven or with center console model motor ?

Happy Boating​

 

[Mechmagcn]

I've got a small engine tach that I'm going to try this evening, it sits on the starter cover and picks up the magnetic field of the flywheel.
Not sure what knowing the rpms now is going to help though, the motor doesn't have enough power to reach max under a load.
Motor is a console steer and has electric trim.

 

[Mechmagcn]

I'm not sure I've been clear about this motor. I'm not doubting anyone's suggestions, but I'm not understanding what the WOT rpms as it's running now has anything to do with it. All I know is the motor would push the boat 24MPH with my wife and I in it or 26MPH with only me. Now it struggles to get to 15-16MPH with just me in the boat. Yes the motor is lugging because it doesn't have enough power to plane the boat.
The day that I ran out of fuel I checked the speed that morning, 24MPH. I was curious because I had just cleaned the pontoons on my barge and gained close to 5MPH and was wondering how much growth was on the hull.
At this point I'll try anything.

 

[Sea Rider]

Check if the small tach you plan to test has programmable spark firing sequence, if not the tach will surely read anything. Yep, a gunked hull accounts for an awful water performance. Would be good to find out which testing procedure did the dealer used to say the motor runs OK. Should have used at least a test prop and ran the motor in a huge water tank facility throughout the whole throttle rpm range, testing in a barrell, muffs without load won't say much.

As of now is not known if the motor has any hidden issues not dected on time by the dealer, anyway will be good to know at which lugging side of the min wot rpm range the motors revs at when achieving just 15-16 MPH.

If the tach doesn't read properly would recommend a multicylinder Hardline Hour/Tach model : HR-8062-2 Check IBoats, Amazon...

Happy Boating​

 

[Mechmagcn]

Ok, borrowed a tach from a friend that works on this motor. With me and a 50# dog in the boat it started out at 4800 WOT and 15MPH. Decided to run it a while, probably 10-12 miles and by the time we got back it would consistently run 5210 and plane out a solid 18 MPH on my GPS speedo. Not sure what could be clearing out as it runs, but got the same results this morning with me and the wife.
I know the dealer doesn't have a test tank, the closest they can get is backing a boat in to a pond beside his house.
I know I have a fuel pressure gauge somewhere, hoping I can find it this weekend.

 

[Sea Rider]

With the motor achieving at best just 5200 at wot it's 800 revs from max 6 K factory stated, Need to prop that motor right, a 10 pitch is too much for that combo, check if can get an OEM 8.5 or 8.0 / 3 blade alum prop, will make the difference if it's just a prop issue and the motor is 100 healthy.

Happy Boating​

 

[Mechmagcn]

if it's just a prop issue and the motor is 100 healthy.

Happy Boating​

I guess I'm not getting the point across that the motor is not doing what it was previously, I'm just frustrated that everyone keeps saying reprop when the performance isn't what it was.

 

[racerone]

Some simple trouble shooting must be done by you.-----No one here can see , feel or hear your motor.----I say it is running on 2 of 3 cylinders.

 

[Mechmagcn]

Some simple trouble shooting must be done by you.-----No one here can see , feel or hear your motor.----I say it is running on 2 of 3 cylinders.

It's running on all 3. Doesn't seem as smooth as it was originally under a load. Just seems to lack that last little bit of power at top end.
I haven't been able to get to my other place yet to try to find the fuel pressure gauge, maybe this weekend. Going to grab my compression tester at the same time.
I'm almost to the point to dump this motor and go back to a carbed 2-stroke, those I can troubleshoot and work on.

 

[racerone]

Very valid point.------The older 2 strokes are easy to trouble shoot.----Repair / rebuild.-----The 4 strokes are great when they run.----Start when you look at the key !!--Expensive to repair if you can find a shop with the right mechanics.