Engine options

[healey8390]

I have an 86' Johnson 110 and am looking at getting something not as old. My boat is a 16ft but heavy for a 16ft and has a deep hull (Airslot 165) it runs about 37mph with two people and fishing gear/coolers etc.

My question is can I get away with a 90hp that is a looper? I'm sure I'll lose some hole shot going from a 4cyl to 3 cyl but since a looper is better than a crossflow from what I've read would I not lose a lot of top speed? I don't mid 30s' ish but don't want to go below that.

 

[racerone]

There is nothing wrong with a crossflow when properly rebuilt.----But a newer 90 HP will make you happy.----New motors start with the push of a button.

 

[healey8390]

There is nothing wrong with a crossflow when properly rebuilt.----But a newer 90 HP will make you happy.----New motors start with the push of a button.

I'm asking because I see some 90hps I like as well and am wondering how much top end I may lose. If you want to buy me new pistons and pay for boring I'll be happy to re-build my engine "properly"......

 

[racerone]

Doubt it.-----But new rings in used pistons is a mistake.------Why do I say that you ask.------Simply because I have looked at the top ring groove under a microscope at 10X magnification.----Amazing what you can see and determine with that kind of vision.-----It is sometimes hard to explain what I know about these motors.

 

[healey8390]

Doubt it.-----But new rings in used pistons is a mistake.------Why do I say that you ask.------Simply because I have looked at the top ring groove under a microscope at 10X magnification.----Amazing what you can see and determine with that kind of vision.-----It is sometimes hard to explain what I know about these motors.

It was sarcasm. I don't understand why you're saying if something is properly re-built? It doesn't answer my question, and referencing a motor I've have put a lot of blood, sweat, and tears into while on a budget mind you isn't necessary in my opinion. I don't know if it was meant a jab but once again it doesn't answer my question.... I haven't given up on it yet but am considering my options.

 

[Sea Rider]

Was the 110 HP Johnny running 37 MPH with a standard non maximized prop as loaded ? As there's no wot rpm info it's impossible to tell at which wot rpm range the motor was revving at. OTOH, you can prop right a 90 HP to run as usually loaded towards middle to max wot rpm range depending if liking more speed or better holes shot which are personal choices. If plan boating fixed loaded as stated, go for a 90 HP and prop it right...

Happy Boating​

 

[Faztbullet]

Find a 115 as a 90 will be a tad slower...

 

[Sea Rider]

Yep an 90 will be tad slower than a 115 but a 115 will guzzle more fuel than a 90, speed versus economy issues, you decide...

Happy Boating​

 

[Faztbullet]

115 will guzzle more fuel than a 90,

Only at WOT.....

 

[Sea Rider]

Only at WOT.....

Yep, was 101% sure that were going to reply that. If we go for the conservatory 10% burn rate per HP rated will have 11.0 gal for the 110 motor and 9.0 gal for the 90 HP one, but with old 2 stroke motors it's actually 12% or tad more burn rate.

Assume the OP likes fishing with a fixed load of two people and fishing gear/coolers etc regularly, if he can prop right a 90 HP to run towards its max wot rpm range will achieve excellent top end speed with much less full consumption per hour if he likes running full hammer down.

Happy Boating​

 

[racerone]

Simply amazing.-----I recall the owner of a 100 HP motor saying-----" This 1966 model100 HP is pretty good on fuel compared to the 59 model 35 HP we had "--------Bigger boat , more people , more skiers.-------He also said " I did not buy this boat to save money "

 

[Faztbullet]

Lets say the motors are pitched correctly and the OP operates his boat at 2/3 throttle at 30 MPH with a 90hp....a 115HP being pitched more will run the same 30MPH at less throttle using less fuel. My 150Hp on my 24ft toon uses less fuel than the 112Hp that was on it at cruising of 22mph....

 

[racerone]

Fuel consumption on a 2 stroke can be confusing.----The little bit of testing I did suggested 3500 / 3600 RPM was most economical on the boat I had.----Light weight 16' fiberglass ski boat with 100 HP V-4.

 

[Sea Rider]

The stated 10-12-14 % whichever fuel consumption rate goes on on a 2 stroke motor is measured running at their max wot rpm range factory stated. With a motor running so will need to throttle less compared to same combo running badly propped to attain same equivalent speed along consuming more fuel due to revving much higher. A correct prop maximization it's definitely the way to go for any boat/motor combo if wanting to get the max out from both.

Load, hull shape efficiency has to do a lot to obatin the best fuel consumption with a given motor/hull. For me 3/4 throttle gives the best fuel consumption rate while maintaining excellent plane at fast cruising speed. Let's see which HP motor the OP's finally goes for ?

Happy Boating​

 

[JimS123]

Simply amazing.-----I recall the owner of a 100 HP motor saying-----" This 1966 model100 HP is pretty good on fuel compared to the 59 model 35 HP we had "--------Bigger boat , more people , more skiers.-------He also said " I did not buy this boat to save money "

Hey, I resemble that remark! That's my saying.

At any rate, here's MY comparison:

25 HP, 1953, 2 stroke - gas hog
18 HP, 1974, 2-stroke - same boat, same trip - just about half as much gas
25 HP, 2007, 2-stroke - different boat (~2x heavier) - same gas as the 18
60 HP, 2017, 4-stroke - different boat (~4x heavier) - same gas as the 18

In other words, 2-strokes greatly improved over the years and 4-strokes blew all their doors off!!

 

[racerone]

I agree 4 strokes are very fuel efficient.----But if you need to go to a dealer for maintenance / service then you spend all the fuel savings in one pop.-----Buddy of mine ( marina owner ) said he loved the 4 strokes.----About 25 years ago it was near $300 for the oil change / filters / sparkplugs / forklift fees.

 

[JimS123]

I agree 4 strokes are very fuel efficient.----But if you need to go to a dealer for maintenance / service then you spend all the fuel savings in one pop.-----Buddy of mine ( marina owner ) said he loved the 4 strokes.----About 25 years ago it was near $300 for the oil change / filters / sparkplugs / forklift fees.

The beauty of a 4-stroke is that the maintenance is so easy. Unless you were totally 2 thumbs anyone can do it themselves.

The components are expensive, though. But everything is available online with free shipping at prices that beat the local dealer.

Time will tell, but my experience is that 4-strokes are way more reliable. For me I didn't buy them for the fuel savings - they just run so much smoother and quieter and I would go that route no matter what the fuel usage was.