Cracked gearcase - ~91 90hp Force

[interalian]

Everything back together. No adjustment was needed after all. The old LU was severely farked.

Here it is idling in a barrel. Idle screws seem best at around 3/4 turn out. She's a smoky pig, no? https://youtu.be/fLmkeDzO10s

 

[jerryjerry05]

The carbs need at least 1 full turn out.
The factory said that the 3 cyl needed to be set at 1 turn out and left there.

​The smoke, most will go away as it gets ran.

 

[interalian]

Thanks. I'll tweak that for the lake test today.

I rigged a drain for the air silencer using a 5/16" r/a fitting with 1/8 NPT threads. Had to drill and tap to fit and use 5/16" line back to the metered fitting (clamped down to the 1/4" with a gear clamp). Carbs were OK inside but got the full "blast 'n' blow" process and are nice and clean inside and out. Linkages all synched too. Took the time to degrease the motor pan as well. I suspect the lower mount perished due to being oil soaked from the fuel/oil constantly draining down the leg.

I've got the shift cable set so neutral is right in the middle of the neutral range on the leg. Any need to tweak that?

 

[jerryjerry05]

The linkage is pretty simple and if the shift cable and the linkage meet in N it should work.

The screws found in the pan: the ones holding the plenum fall out a lot.
Thread locker helps.

 

[interalian]

Here she is, running. Not very strong out of the hole, but it's an 18.5' cuddy. Pops best if trimmed up a bit for hole shot.

Boat doesn't have a tach, but sounds like it's a bit overpropped, running lower than max RPMs. How does it sound to the tuned ears on here? No idea what rated powerband is for this motor either.

Bear in mind we're at 3300 feet elevation, so I would expect it to do more than 33 on the salt. On board speedo is dead nuts match to GPS, which is a rare thing for boat gauges, no?

https://www.youtube.com/watch?v=Mzkwv6mttso&feature=youtu.be

Thanks to all for the Force tips!

 

[Nordin]

Yes it sounds a bit low RPMs.
What pitch do you have, 19 or 21?

The LUs had three different ratios I Think. Are not really sure about the 2 piece drivshaft typ but there were 1,73:1, 1,93:1 and 2:1 I believe.
Maybe jerryjerry would know and chime in.

2 in decrease of pitch would high the RPMs about 200-400.

 

[interalian]

Yeah, sounds like about 4000-4500 max to me. The LU we got is off a '91 90hp, so I would presume it's the same ratio as the original one. Before the repair, we got only 30mph. I suspect running rusty gears with no oil and a blown out middle cylinder bypass port gasket reduced the shaft HP by a few.

Boat's for sale and the prop is a bit on the dinged up side. I would be telling any new owner to buy a replacement prop of a lower pitch, but I'm not sure where/if it's even marked on these other than the part number. You can see by the hole-shot that it could use help from a shorter prop.

Here she is from the dock. "Salty Kiss" - make of the name what you will, it was always a freshwater boat...

https://youtu.be/Q5jiPdO4uog

 

[jerryjerry05]

Sounds like???? No tach?
​We had a guy work for us that timed motors by ear.
​I had to fix all of his work.

​Good luck with the sale!

 

[interalian]

Yeah, I know. Timing by ear? No. Judging WOT RPMs, sure. This clip of my 140 'rude build is flirting with 6000 - ear confirmed by tach. https://www.youtube.com/watch?v=Kt4AFg92Cc0 And if I can bump 6k at 3300' on a 17" wheel, my replacement is a 19" wheel.

Neighbor is happy, sale pending today. Won't be my problem anymore.

 

[ondarvr]

I have a LU off of a 90hp Force in my shop, it's been sitting there for years, had I noticed this earlier you could have gotten it for cheap.

 

[interalian]

I have a LU off of a 90hp Force in my shop, it's been sitting there for years, had I noticed this earlier you could have gotten it for cheap.

Bad timing. Where are you located?

 

[ondarvr]

Seattle area, but I'm in Kelowna frequently.

 

[interalian]

Maybe next time