90TLDI power issue

[barramundiman]

I noticed this quote on another topic in this forum ...

"I tried this on 3 different 90 TLDI motors and four boats, my conclusion after all that messing around was that the tldi 90 only has about 78 to 80 true hp."

I own a 90TLDI and wonder if there is some truth in this - my 90TLDI revs to only about 5100rpm with a 15 inch pitch prop. I expected better. I have tried various props. I know another person who says his 90TLDi would not rev high on a standard 90 prop either.

The motor performs flawlessly otherwise and is economical, but then I suppose you would expect economy if it is actually an 80hp motor. I am not running the engine at altitude.

I raise the subject because I wonder if there is a reason why some motors perform less well. Maybe they all don't rate the full 90hp. I would expect there would have been many words about this in various forums by now if it were true.

I don't want to go down in prop pitch.

Has anyone rated these engines at the prop? Is there an independent government test?

 

[TOHATSU GURU]

Re: 90TLDI power issue

No truth to it at all as the governement is the ONE who rates the engine's hp at the prop and there is no such thing as a standard prop. There are a variety of pitches available from a variety of manufacturers and propeller selection is done by trial and error to get the best result possible in any given application.

 

[barramundiman]

Re: 90TLDI power issue

The problem here is that you stick the same prop on two different motors that are the same size and one does 600rpm less than the other.

 

[TOHATSU GURU]

Re: 90TLDI power issue

Are they both 90 TLDI X models mounted identically on the same boat, with the same load and operated at the same trim angle by the same operator? If they aren't then any comparison between the two is pointless. If they are then one engine is sick.

 

[chevyjet]

Re: 90TLDI power issue

The reason you are having trouble getting the power you think you should out of your tldi 90 is they are rated at 5800 rpm. They do not have the torque of some of the other 90s out there. I posted the thing about the lack of power and I found if you run the tldi 90s at 5700 rpm they pull not too bad, but the oil burn is just nuts at that rpm.

 

[TOHATSU GURU]

Re: 90TLDI power issue

They are rated at 90 hp at 5500 RPM, not 5800. Oil consumption at 5500 RPM is .225 gallon per hour. The oil consumption at 4400 RPM is .087 per hour. The oil consumption rate increases as the fuel consumption rate increases with the "jump" occurring at about 4500-5000 RPM or at about 85% of WOT. Trailer Boats Magazine did a comparison of all 90's a few years ago that is still available online. Their test data is accurate enough, although some of their conclusions fly in the face of that data. I guess that's typical of people re enforcing their own biases.

 

[whitewater90]

Re: 90TLDI power issue

I see the Grue is still sticking up for the oil burners and accusing people of bashing them. The 90 TLDI definitely burns lots of oil for the power they produce. I had a 75 Yamaha on my boat before I got this 90TLDI and I have to run the same prop on the 90 as the 75 to get the same RPM, they have the same gear ratio so the 90 isn't a 90.

 

[SlowMo]

Re: 90TLDI power issue

I agree 100%, I have a Tohatsu 90TLDI and it is slow as hell.

It is reliable, and economical under 4400rpm, but I'd rate it at just 70hp.

On a 4.5m pressed alloy boat I am getting 52km/h at 5100rpm.

I had an old Johnno 50hp 2-stroke twin on the same hull and it went almost as fast as the 90hp!

The same hull had an old Yamaha 85hp 2-stroke and it did 65 km/h.

The 90TLDI swings a 15" prop at only 5100rpm. The dealer says the engine is fine.

I have tried different props, and tried raising and lowering the engine.

I do not use the engine at altitude.

***Note this thread also ... http://forums.iboats.com/showthread.php?t=269898

Who tests engines for correct rating?

 

[TOHATSU GURU]

Re: 90TLDI power issue

I disagree 100%, I have a Tohatsu 90 TLDI and it is fast as hell.

It is reliable and economical at all RPMs, and I would rate it at 110 hp.

On a 4.5m presswed alloy boat I am getting 82lm/h at 5500 rpm.

I had an old Johnso 50 hp 2 stroke twin on the same hull and it was extremely slow.

The same hull had an old Yamaha 85 hp 2-stroke and it did 47 km/h.

I use the same prop for every appplication and hung the engine blindfolded up side down in case I flipped the boat

I use the engine in the summer time on my submarine.

***Note this thread also ... http://forums.iboats.com/showthread.php?t=269898 (The same tired old foolish crap repleated by the same tired bashers)

In the U.S they are government certified at the propshaft.

 

[SlowMo]

Re: 90TLDI power issue

Shame Tohatsu Guru, I was hoping you might be the one with an answer.

I like my Tohatsu because it always gets me home, it
just takes a lot longer than everyone else.

The lack of power is considerable.

I wonder if it is possible to detune them, or increase the oil input. Perhaps it would be in a distributor's best interest to do this to decrease warranty claims. It's the only thing I can think of that may have happened.

Otherwise, it has got me beat. If it put out 90hp I'd have a great motor, but I reckon it puts out 70hp.

 

[JB]

Re: 90TLDI power issue

Few boaters seem to understand that top speed is more a matter of hull condition, propping, rigging and balance than a seat of the pants guess at "HP".

Subjective opinions are no substitute for scientific measurement.

The TLDI 90 must put out the advertised power, +/- some small percentage, on a dynamometer, just like every other outboard sold in the USA. Putting one on a boat that might not be perfectly rigged and collecting OPINIONS is an unacceptable way to assess torque or horsepower.