1979 I-6 90 HP "Pops in and out of gear"

[spike_michael]

Oddest thing...
First run of the season for my Larson G-3 with a Merc 90 HP inline ...
Got out on the water and hops right up on plane at no more than say a500 RPM well I slowly opened it up a little, tach died... (a problem with the wiring I am sure) so no more #s for ya but as I was cruising along all of a sudden the RPMs shot up like I had ejected my prop! I (obviously) backed the throttle down in a hurry and all of a sudden I was back in gear. well...
I turned around and headed downstream for home and babied the throttle coming in. None the less the "gear" kicked out a few more times on the way back.
I have no idea on this, I will look into any and all thoughts!
The manual does not address this in the troubleshooting symptoms.

i love flying in this boat it is one of the nicest smooth runners I ever played with.

Thanks

Oh by the way anyone want a G-3 with an I-6 on a trailer? nice boat... just seats 4 and I need 6. Transom is getting spongy, time for new plywood, but one fast skiboat! Keep up anwith the jetskis and then some.

 

[tashasdaddy]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

sound like you hae a spun prop. take the prop off with a permanent marker draw a line across the prop,,across the hub and all. pt it back on, take it for a spin, make it jump out of gear again. then check the prop, if line are not lined up the inner hub of the prop has to be rebuilt. any prop shop can do it. or call marina ask who they get. if the line are still conected , then yu have a lower unit problem, probably the clutch dog.
thanks for the offer, but i've got a 71' 1350

 

[tashasdaddy]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

also this is the first run of the season, make sure it is shifting all the way in gear. cable may be going (streching)

 

[spike_michael]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

clutch dog...
clutch dog...

is it house trained?

can't find "clutch dog" in the manual

have other props, could swap one out

 

[tashasdaddy]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

open the cover, on the left side from the back, where the cable go in, and check that the cable is moving the shift slide all the way for forward. these cable go bad and don't do there job properly. you may have to remove the throttle cable to see. there is and adjustment there also.

 

[spike_michael]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

what is the likelyhood of the clutch dog over the cable adjustment?

Everything is falling apart on me today...
lawnmower...
garage...

 

[tashasdaddy]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

check the cable first, it can be adjusted. you don't want to keep jumping out of gear, to test with the other prop. if the cable appears to move the slide all the way, put the other prop on and give it a try. it would be nice if it is just the adjustment, or a spun prop. the prop is built with the inner splines held to the outer prop by a big rubber bushing, sometimes these fail and the inner spins (slips) faster than the blades, thus the reving and no power. (kinda like driving down the road in a straight stick car and putting the clutch in and not releasing the throttle)

 

[spike_michael]

Re: 1979 I-6 90 HP

Re: 1979 I-6 90 HP

Thanks for the concepr on the spun prop.

I may or may not be able to deal with it since the boat et al is for sale.

The spongy transom is likely to give me more headache than the spun prop...

When under thrust it seems I bent my bilge plug rather nastily.

I am wondering how much "torque tilt" the engine produced.

Since I was the only boat saavy person in the boat and I was on the throttle I didn't make any observation directly.