5hp 2 stroke or 6hp 4

[Tommy c]

....for a 3+m sib?
I'm familiar with 2 strokes but not 4's.
Been told from 1 source single cylinder 4's are plastic push rods and to avoid.
Is the extra horse going to noticeable.
The 2 stroke is 15 years older than the 4.
Purchase price not an issue

[jeffstevens763@g]

6/4 don’t see how plastic would stand the heat if that’s true

[Searider]

I had a 4hp 4 stroke Yamaha which vibrated a lot.
Seemed worse than the 5hp 2 stroke i subsequently had.

[Tommy c]

My mistake, just re read what he said

’single cylinders have pushrods which can wear the pressed metal guides causing internal chaos. Camshafts and timing gear is plastic too.'

[TmMorris]

There's more gubbins inside a 4 stroke that's for sure but if it's looked after it's not really an issue.

Personally, I'd favour the one that was lighter and just easier to carry and work on which would probably be the 2 stroke if they're in equal condition but a 6hp 4 isn't going to be that much heavier? and not having to mix oil is a benefit.

[jeffstevens763@g]

Originally Posted by Tommy c

My mistake, just re read what he said

’single cylinders have pushrods which can wear the pressed metal guides causing internal chaos. Camshafts and timing gear is plastic too.'

Again camshafts wouldn’t last five mins hardened steel wears that why valve clearances have to be checked regularly.

In my experience all the main manufacturers are good I’ve never known combustion engines with plastic inner working parts I might be wrong but I’ve stripped a few over the years never seen them but heat,wear & strength would be the issue.

[beamishken]

Originally Posted by Tommy c

....for a 3+m sib?
I'm familiar with 2 strokes but not 4's.
Been told from 1 source single cylinder 4's are plastic push rods and to avoid.
Is the extra horse going to noticeable.
The 2 stroke is 15 years older than the 4.
Purchase price not an issue

My preference at that size would be the two stroke, far simpler lighter & no oil to worry about spilling. Small 4 strokes are ok but they wont live as long as the old school two strokes, carbs can be a pain as they easily get blocked & aren't easy to clear due to the tiny galleries. Id guess the 5 is a Yamaha which you need to be careful of the gearboxes which die from internal corrosion otherwise they are bullet proof. My next choice would be the 2 cylinder 8hp 2 stroke excellent little engine & very punchy for its size

Originally Posted by jeffstevens763@g

Again camshafts wouldn’t last five mins hardened steel wears that why valve clearances have to be checked regularly.

In my experience all the main manufacturers are good I’ve never known combustion engines with plastic inner working parts I might be wrong but I’ve stripped a few over the years never seen them but heat,wear & strength would be the issue.

Many engine parts are now plastic/composite including gears a couple that come to mind:- sthill chain saws have plastic crankcases & 150hp Yamaha has plastic balancer shaft gears probably plenty other examples out there

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[jeffstevens763@g]

Originally Posted by beamishken

My preference at that size would be the two stroke, far simpler lighter & no oil to worry about spilling. Small 4 strokes are ok but they wont live as long as the old school two strokes, carbs can be a pain as they easily get blocked & aren't easy to clear due to the tiny galleries. Id guess the 5 is a Yamaha which you need to be careful of the gearboxes which die from internal corrosion otherwise they are bullet proof. My next choice would be the 2 cylinder 8hp 2 stroke excellent little engine & very punchy for its sizeMany engine parts are now plastic/composite including gears a couple that come to mind:- sthill chain saws have plastic crankcases & 150hp Yamaha has plastic balancer shaft gears probably plenty other examples out there

Sent from my SM-G950F using RIB Net mobile app

No dought but camshafts ?

[beamishken]

Originally Posted by jeffstevens763@g

No dought but camshafts ?

Camshafts seems a step too far but you never know, cam gears wouldnt surprise me & maybe they use a steel sleeve for the cam lobes. I'd be interested to see one if they actually are plastic

Sent from my SM-G950F using RIB Net mobile app

[jeffstevens763@g]

Originally Posted by beamishken

Camshafts seems a step too far but you never know, cam gears wouldnt surprise me & maybe they use a steel sleeve for the cam lobes. I'd be interested to see one if they actually are plastic

Sent from my SM-G950F using RIB Net mobile app

Yep me too feasible I suppose never say never

[909]

8 2 stroke
or 15 2 stroke
You can barely get on plane with a 5

[pumpkinking]

Originally Posted by Tommy c

....for a 3+m sib?

I'm familiar with 2 strokes but not 4's.

Been told from 1 source single cylinder 4's are plastic push rods and to avoid.

Is the extra horse going to noticeable.

The 2 stroke is 15 years older than the 4.

Purchase price not an issue

I have had a Suzuki DF6AS for two years now, I love it. Weighs about 26/27kg when wet, which is perfectly manageable for me.

It planes our 3.3m excel Volante with just me easily, nips along. With 2 average build adults and some “stuff” in the boat it also planes well - see my recent thread with video showing this.

I was buying new so was 4stroke or nothing for me, I’ve had no issues with oil - the motor can be stored on any of three sides, just keep the head above the prop.

Even serviced it myself for the first time this year (decided cost of professional servicing to maintain the warrantee was not worth it) and it was easy to work on.

Each to their own, 2 stroke has its perks, namely weight, but I like not having to mix oil with the fuel any more like I did with my old 2.5hp 2 stroke as I don’t use the boat loads and I can just syphon the remaining fuel from the boat’s 12L tank into the car at the end of the holiday!