1971 35HP Lower unit problems

[Jkoosh]

Hello all,

So I recently bought a boat with a 1971 35hp chrysler (model 355HC and serial 3486), and after setting it all up it has run for 20+ hours, it just started acting up!

I originally had issues with the shifter, where I need to push slightly past neutral on the controls for the engine to actually get out of a gear (push slightly into reverse to shift into neutral when engaged in forward...and vice versa).
But now the problem has arisen where after shifting into gear, at about 1/2 throttle the engine slips out of gear and loses power (engine stills revs higher and higher). This happens in both forward and reverse.

Is it most likely the clutch dogs, or that the gears may have never engaged enough so that they now slip when higher torque and rpm's are applied?

I am looking to get parts to fix it, (College student doing research right now), and I think I need to get lower unit housing's since the current ones look bad.

If anyone has taken one apart, after removing the lower unit, how do the 2 parts separate? (nut and washer in lower behind gear, and second in front of shaft?)

Would I be better off finding a complete lower from another make? (rumor is that other similar age lower's use the same connections and move the water intake to the side of the lower unit?)

Thanks all!
John

 

[wickware]

I have a 1970 35hp Chrysler (owned since 1984-85 but I have not experienced your issue. The pros will jump in with experience. I would question the following:

1. History: Has this always been an issue (yrs/hrs) or did it start after removing the L/U shift coupling? Could this be caused by the shift rod not being installed centered.
2. Has your L/U oil shown any excessive metal from wear?
3. I feel my 1970 35hp lower unit is as good as new due to maintenance, 6-8 hrs approx use a yr and solid shifting.
4. Would shifting at the shift rod vs control and forcing the prop to turn by hand have any proof on the conditions of the dogs?

 

[Nordin]

All LU from 35, 45, 55Hp from 1965 up to 1975 will fit. In 1976-77 they made a new 35 and 55Hp with a different LU. You maybe have to mod with the shiftrod it was change in 1974-75 from nutcoupler to cottorpin in the Connection for shaft low to intermidiate.
The earliest LU 1965-66 the propshaft did not have spline.
The 45Hp LU was the same from 1966-1984 when Chrysler Went out from OB buiesness.
Force LU units 45-50HP will also fit.

 

[wickware]

Thanks Nordin! Is there a good test for bad dogs vs adjustment issues before a tear-down or replacement?

 

[Nordin]

No nothing I know. Make sure you adjust properly at the shiftshaft. Run the Engine, if it slips disconnect the remotecables and shift by hand.
If it still slips.....tear-down and check for rounded edges at the clutchdog and the gear.