NIssan 90 prop pitch

[grnwtrcruzn]

I just put a 92 Nissan 90hp on a 96 boat that I had purchased with a blown engine. I just took it out a while ago and was a little disappointed at the performance I was getting out of the 90. I was wondering what sort of performance others where seeing out of their 90's and what sort of prop/pitch you're using.
Thanks!

[Hardcrab]

grnwtcruzn,
First, Nissan is simply a rebadged Tohatsu.

We run a 2004 Tohatsu TLDI 90 on an M.
We started with a 14" diameter X 13" pitch prop.
Semi-lightly loaded, no ballast, the engine would only get to 48-4900rpm, wide open throttle, out of the 5200-5800 factory recommendation.
I don't recall the speed, but somewhere over 23-25 knots.
In car talk, it was "overgeared", like climbing a hill in high gear, and "lugging" the engine.

I next went with a 14X10" pitch, and the engine would easily bounce of off the max redline of 6200, and less than 20 knots.
Now it was "undergeared", like running around in first gear all the time with screaming rpm's.

We settled on the big-eared 14X11'pitch from Quicksilver and get around 54-5500 rpm WOT, right in the middle of factory spec and 22-24 knots depending on seas and loading.
All speeds are GPS and ballast empty.

I would start at the 14X11' pitch and see what max rpm's you can get with your standard loading.
The goal is somewhere in the 52-5800 window. (at least for mine, not sure about yours)
Your older engine is carbed and your X may make some differences in the final choice.
It may have been proped for a runabout, with pitches up to 14"X22".

[Bobby T.-26X #4767]

the 1992 - 90hp is an M90 2-stroke no longer available in the U.S. it's actually abt 20# lighter than the current TLDI model sold in the U.S.
that said...i agree w/ Hardcrab on the prop selection.
I, too, run a Quicksilver 14" x 11 pitch. it's got large "dog-ears" which serves to move alot of water. it's basically a prop created for a pontoon boat.
works great for a Mac!




Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[Octaman]

Greetings to all from Athens, Greece

Hardcrab,

I have a SUZUKI DF70 (1.300cc) on my 2004 Mac . It has served me well over time but am now considering to re-power, primarily for the sake of having the assurane of a new engine on my transom.
I am considering the TOHATSU TLDI 90 that has almost the same cc but is two stroke and delivers more hp, in the hope that I will get a little more umph out of this motor which I feel I lack and require.

I have been using a modified 14'x13' 3-blade solar prop; a section of the trailing edge shaved off at the prop shop to take off some load and achieve rpm in the range of the engine (5.250 to 5.800) - I get about 5.500 rpm
This propeller has given me speeds of 15knots to 16.5 knots with empty ballast tank, two persons and gear fully loaded @ 4.900 rpm and 5.200 rpm respectively.

You have an M with the 90 tldi, therefore I would be very, very interested to hear more on performance and fuel and oil consumption with this engine.

Lastly, if you were to do it all over again, would you go for the same 90 or would you go for the 115 tldi ???

Thanking you in advance for your input

Octaman

[TexasDan40]

grnwtcruzn,
First, Nissan is simply a rebadged Tohatsu.

We run a 2004 Tohatsu TLDI 90 on an M.
We started with a 14" diameter X 13" pitch prop.
Semi-lightly loaded, no ballast, the engine would only get to 48-4900rpm, wide open throttle, out of the 5200-5800 factory recommendation.
I don't recall the speed, but somewhere over 23-25 knots.
In car talk, it was "overgeared", like climbing a hill in high gear, and "lugging" the engine.

Careful Hardcrab! Last year I got beat up pretty hard here for claiming my 26 topped out at 28 mph...GPS & paddlewheel. I'm a believer...it's all in the prop.

Te

[raycarlson]

I can't attest to the 90HP motor as i made the mistake of going with the small reccommended 50 HP.a mistake that will cost me thousands more to repower versus having a 90 hung when the boat was purchased new.But i can say after owning about every brand of outboard made that the nissan/tohutsu tldi series of engines is the best engine I've owned to date. the direct injection burns clean,starts instantaneously,has onboard diagnostics computer(have to have service manual to translate signals).I have run mine across the gulf of calif at 1500rpms for 8 hours nonstop getting 10mpg with no plug fouling or nary a stumble when the motor was accelerated.It also has a 28 amp alternator which was the largest i could find at the time,and does a much better job charging your batteries than some of the other brands of motors with only 6-10 amps of power.

[JonBill]

I too run a Tohatsu 90TLDI but it's on an M boat and recently reproped with a 14"x10" Quicksilver aluminum. I went with the lower pitch this time because the M is heavier than the X without water ballast by about 300 pounds of permanent ballast if I remember correctly. Plus I seem to always carry a lot of "stuff" which weighs the boat down and have about 6 coats of epoxy and about 4 coats of bottom paint on the bottom as I have the boat in a wet slip in Palacios TX.

Previously I was running a Quicksilver 14"x11" which was the prevailing collective wisdom of those who had the foresight and an adventurous enough spirit to properly power their 26X and M's with the lightest and most reliable 90 HP motor in the world. However while I was getting the higher end speed the RPM's with the 11" pitch on my overweight M was keeping the motor running at the very bottom of the acceptable RPM range at best. With the 14"x10" prop the motor now runs at a perfect 5800 RPM at the higher end of the proper range without ballast which is much better for the engine and runs somewhere around 5400 or 5500 with ballast. The boat plains at a higher RPM now than it did before at around 4,000 or 4,200 RPM.

Gas mileage with the lighter pitch still seems to be just fine with being able to run down to matagorda island and back (last week with just me and my 4 year old grandson) on one tank (12 gal.) with plenty of fuel to spare in that tank when we got back and that was on a day when there was no wind. That was with no ballast and running at a fuel saving RPM just over the hull planning speed at about 4200 to 4400 RPM. That's about the same performance it did before with the heavier pitch. I'm sure it must be somewhat worse but then again maybe not since the engine was near lugging and now it's pitched properly.

I misplaced my GPS and haven't check the SOG lately, but it seems find to me just using judgment. I'm sure it's down a little but really didn't buy the M as a race boat so max SOG was not my greatest concern obviously.

I also switched to the newly recommended spark plugs about two years ago but didn't have opportunity to run the boat on the water for a couple of years due to a family tradgedy. But this year we have been out several times and the motor runs noticeably better with the new spark plugs. Tohatsu must have experimented with multiple plugs just prior to that time frame and came up with a new recommendation for the 90 TLDI. I can't tell you from memory what they are but they are recommended on the website now so don't just buy the same old plug number when replgging your 90 TLDI but check out the new plug recommendation and I highly recommend it for an overall smother running and better performing engine.

Well we have rain with the low in the 30's today and tonight but by Sunday it will be back up in the low 70's so hope to get out on her again Sunday afternoon with the grandkids.

Kind Regards,
JonBill

[Octaman]

I misplaced my GPS and haven't check the SOG lately, but it seems find to me just using judgment. I'm sure it's down a little but really didn't buy the M as a race boat so max SOG was not my greatest concern obviously.

Hey JonBill, if you could get some figures from your GPS whenever possible, that would be most appreciated.

grnwtcruzn,
We settled on the big-eared 14X11'pitch from Quicksilver and get around 54-5500 rpm WOT, right in the middle of factory spec and 22-24 knots depending on seas and loading.
All speeds are GPS and ballast empty.

Hardcrab - I find 22-24knots with your 90 tldi and a 14x11 Quickilver prop extreeeemely good speed . Even 20 knots would make me extremely happy. What about consumption of fuel and oil?

Octaman

[Catigale]

Keywords

Nissan TDLI 90 prop pitch performance mileage speed M

[Hardcrab]

Octaman, sorry for the late response, I've been on vacation and away from any computers.

All of my speeds are from GPS in the Pacific ocean.
1-2 foot swells at 14 sec are the "norm" in Santa Monica Bay.
I seldom to never run at WOT. Burning up gas is not my hobby and the seas don't really allow for it anyhow.
My speeds are without any water ballast, something I always do when hi-speed motoring (only) is the goal, such as a 33 mile run to Catalina.
My boat has no bottom paint, and is very lightly loaded without any extra/unnecessary junk aboard.
Extra junk is a killer for motor or sail. This is not a trivial point.

On a typical 33NM trip to Catalina, I'll run about 3/4 throttle, 45-4600rpm, 16-17 knots, about 11 gallons for the trip with dinghy aboard, (just over 12 gallons towing it), 14 X 11 prop.
Oil consumption is hard to figure due to the variable oil injection mapped to rpm's, but I'm sure I could do three hi-speed one way trips without looking at the 1 gallon oil tank.
At my 99% of the time /under 1400 rpms usage, I tend to forget about oil consumption at all.
I have had zero problems with the 90 TLDI. It starts with a touch of the key every time, even after several weeks of non use.

If I were forced to complain about something, it would be the noise.
It's loud at higher speeds.
But my 2 hp Honda is loud on the dinghy.

That's why we mostly sail, trading noise for peace and quiet.

[Octaman]

Thank you very much Hardcrab for all this valuable infomation. All being duly evaluated for my decision to come.

I hope you had a great vacation.

--------------

grnwtrcruzn - I hope you are benefitting from these postings as much as I am. It was your initial posting after all . . . Thank you for starting it.

Octaman

[grnwtrcruzn]

A bit of a late reply but thank you to everyone for the advice on the proper pitch of the prop. I finally said the hull with the house projects and took the boat out last weekend. I was seeing 19mph with full ballast and 3 people on board! Most of the day was spent cruising around 8mph(1800-2000rpm) and I burned about 5 gallons.... Not to shabby. I did notice that it was still pushing a lot of water and not really making it up on plane so I do believe there will be some transome wedges in my future...

[beene]

You will be very surprised with the difference just a few degrees can do to a motor tilt in.

I have the wedges and if I tilt up just a bit:
speed goes down
start pushing water
increase wake
water through the keel housing
poor steering

My wedges are 5deg

G

[Catigale]

Careful Hardcrab! Last year I got beat up pretty hard here for claiming my 26 topped out at 28 mph...GPS & paddlewheel. I'm a believer...it's all in the prop.

I remember that...why were you reporting such a slow speed??