flywheel interchangeability

54bobby

Petty Officer 2nd Class
Joined
Dec 12, 2010
Messages
181
guys, i have a 63 18hp, mod. #18302L, my question is, will flywheels from the other years particularly, the ones off of 66.7.8.and 9 fastwins and the 25 hp sportster fit the 63 engine. the flywheel on the 63 is very robust and much harder to pull start than the ones on the later engines.i'm trying to make it a little easier on the grand kids and wanted to swap them around if compatible.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,030
Perhaps you need to look at the recoil starter.------They are brilliantly designed to make rope starting easier.----The sheave is eliptical to help on the compression strokes.----Flywheels would have no effect on the starting effort.----Someone else will post more details on this simple fact !!
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
The tapers on all the ones you mentioned are the same. Likewise, they all have the elliptical recoil starters and Universal Magnetos. Beyond that, I'm not aware of any other differences.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Heavier would actually work better. More mass moving and better momentum.
 

54bobby

Petty Officer 2nd Class
Joined
Dec 12, 2010
Messages
181
54bobby----- is overthinking in my opinion.

i may be over thinking, wouldn't be the first time for me. lol but the engine runs great so that leads me to believe that there's no issue with the internals causing the harder than usual pull. iv'e swapped on 2 other recoil starters that pull other 22 cube engines just fine and same tuff yank but those recoils i took off engines that were 1969 models. apparently in 69, they went from a thicker more robust toothed wheel to a thinner lighter one. from what i can tell, pre 69 was individual parts composing the flywheel and 69 and on it was an assembly, or that's how i'm understanding it from the schematics. my question was, would the newer lighter wheel translate to an easier pull. i'm swapping it out this weekend and will report back. if that doesn't work, what would be the cause of this fastwin being such a hard turn over?

oh yea, if the recoil was out of time so to speak, would that make it a harder than usual pull but still start the engine? she's a one pull start motor but what a pull it is.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
One possibility: Your 22 incher may have unusually high compression because some genius may have tried to make a 20 or 25 out of it by swapping heads or pistons. Just a speculation.

To avoid hard feelings, I'll not address the recoil starter issue. But I say that is not the hard pull cause.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
I had a '50s 7 1/2 that pulled over hard -- felt like very high compression, as FR describes. It ran beautifully, though, so I sort of considered the hard pull a feature. Once it was warm, it pulled over normally. (Motor is long gone, but not the mystery.)

I'm inclined to think the 18 is just a hard pull for a kid. Maybe a squirt of light oil into each cylinder would help before going out, followed by pulling it over slowly. I'm not sure I would go through all that, but a really dedicated granddad might! :)
 

ci2hi

Cadet
Joined
Jun 29, 2009
Messages
19
Installing a lighter flywheel may cause your engine to not troll quite as well. I like 54bobby's answer that the first compression stroke may be when the pulley is on the short radius of the pulley. Easy enough to check that simply by pulling the rewind and looking.
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,446
Those elliptical ‘pull o matic’ or whatever they’re called are always timed to be easier to pull through compression stroke. The only changeable setting (rope length) only changes how far the handle pulls out before pawl engages flywheel..
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Those elliptical ‘pull o matic’ or whatever they’re called are always timed to be easier to pull through compression stroke. The only changeable setting (rope length) only changes how far the handle pulls out before pawl engages flywheel..

That is what I wanted to say but didn't.
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
7,985
Are you sure the recoil itself is cleane? Sometimes people try to grease them and make it worse.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
Think I would work to make sure ignition tuning is spot on, and the grandkids know the proper starting procedure. If it pops on the first pull, there won't be any complaints.
 

54bobby

Petty Officer 2nd Class
Joined
Dec 12, 2010
Messages
181
Think I would work to make sure ignition tuning is spot on, and the grandkids know the proper starting procedure. If it pops on the first pull, there won't be any complaints.

replaced both coils, points, condensers, leeds, plugs, rebuilt carb, removed electric start system (thats gone on my 25, lol)gears and dog are pristine, new impeller, housing, and base plate, and t-stat. needs a head gasket, just spotted the smallest drop of water seeping from top starboard side real close to the thermostat housing. engine is in terrific shape not a single buggered up screw on it. all paint clean with no chipping under the hood. motor cover is faded and graphics need replacing. i have both colors of 1963 fastwin paint and decals ordered. engine will be on the water for years to come. and the kicker is, i paid 125 for it with electric start from the factory.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
Good prep, sounds like. Measure spark with an adjustable open air tester (not an inline), available inexpensively at auto parts stores. Look for 3/8" or more (I think) -- not directly related to plug gap. If spark is less than perfect, I would clean and readjust points. You can tweak the coils through the triangular cover on the top of the flywheel.
 

54bobby

Petty Officer 2nd Class
Joined
Dec 12, 2010
Messages
181
Good prep, sounds like. Measure spark with an adjustable open air tester (not an inline), available inexpensively at auto parts stores. Look for 3/8" or more (I think) -- not directly related to plug gap. If spark is less than perfect, I would clean and readjust points. You can tweak the coils through the triangular cover on the top of the flywheel.

what do you mean by (tweak the coils?) or did you mean points?
 
Top