1977 9.9 johnson

[wrmdunker]

Hello All,

Looking to buy this Model number 10EL77A. Cowling has a ding on the underside that was epoxied. Mark is located above a silver disc/plug on the block about 3/4 inch dia. What is this plug (starboard side) and would it have blown and cracked the cowling?

Any thoughts would be appreciated and/or personal experience with this motor. Block looks very clean, good hoses, good coil housings and good pee stream.

Thanks

WD

 

[raczekp1]

Re: 1977 9.9 johnson

this silver plug is ID tag, the same as is on transom(its a copy).
this is model and number stamped.
try copmpresion test.
3 puls on each spark plug hole give you compresion readings.
100 psi or more means ok
60 psi means powerhead cals for rebuild

 

[wrmdunker]

Re: 1977 9.9 johnson

Thanks for the info. Any knowledge on the function of this plug and why or if it could have blown?

 

[raczekp1]

Re: 1977 9.9 johnson

this plug cant be blown.under this plug is floating water to cool down cylinders.so the preasur is only 5 psi or so.
this plug can be removed only in mechanical way.
only one purpuse in removing is to hide ID numbers.
the best info you wil find in http://www.sschapterpsa.com/ramblings/Ramblings.html
go down at the botom of this page

 

[Rick.]

Re: 1977 9.9 johnson

EL designates an electric start with a long lower unit. Do you require the 20inch lower unit? If not I would pass on it. Best of luck. Rick.

 

[wrmdunker]

Re: 1977 9.9 johnson

raczekp1: Nice website. Thanks. I have a lot of reading to do.

Rick: I hadn't thought about the shaft lenght. Its mounted on a 16 foot jon boat and my son wants it for shooting carp in shallow water... Also has a 55 pound thrust bow mount for tight spots so he may have to tilt the Johnson in shallow water. A 15 inch may be better. Will the 20 affect how it handles?

WD

 

[Rick.]

Re: 1977 9.9 johnson

Yes it will affect it negatively. For a john boat I would want a 15 inch not a 20. I'd keep looking or you can convert it to a 15. I think the only purchase would have to be a new drive shaft as the lower unit has a five inch extention you can pull out and then cut five inces from the water tube. Never done this but lots have. Leeroy has built a superb website and he probably has an article about converting the shaft length. Rick.

 

[JDusza]

Re: 1977 9.9 johnson

It's not the length of the boat it's the height of the transom; 15" or 20".

With a 15 " transom DO NOT use a 20" engine shaft. It is extremely dangerous!!! I assume you love your son and want to keep him!!!!

The longer shaft puts the prop lower in the water which extends the moment arm of torque (of the boat/engine as a pair) and this will tip the boat when steering and THROW YOU OUT; especially on hole shots. If you turn the engine before you gun it, you'll be in trouble. The prop needs to be close to the hull. You want the anti-cav plate to be about an inch off the hull.

If you are hell bent to go this route, wire in a kill switch that attaches to your body it. You really shouldn't fool around with this.

Also, in converting long shaft to short shaft you need a shorter water tube, check; a shorter drive shaft, check; AND a shorter shift rod. With these parts the conversion is easy.

All the best,
J

 

[wrmdunker]

Re: 1977 9.9 johnson

Well I went to take another look at the boat/motor and to my surprise it has a 20 inch transom. Big boat and they may not make them like this anymore. Its a Monark 1652 and the deck is 52 inches wide. Boat is rated for 1100 pounds. So seems like the long shaft is correct. I didn't want to get into cutting it down. The shaft alone was $163. Thanks to all for the input. I pulled the trigger on the combo. Will post pics soon.

 

[Solittle]

Re: 1977 9.9 johnson

It's not the length of the boat it's the height of the transom; 15" or 20".

With a 15 " transom DO NOT use a 20" engine shaft. It is extremely dangerous!!! I assume you love your son and want to keep him!!!!

The longer shaft puts the prop lower in the water which extends the moment arm of torque (of the boat/engine as a pair) and this will tip the boat when steering and THROW YOU OUT; especially on hole shots. If you turn the engine before you gun it, you'll be in trouble. The prop needs to be close to the hull. You want the anti-cav plate to be about an inch off the hull.

If you are hell bent to go this route, wire in a kill switch that attaches to your body it. You really shouldn't fool around with this.

Also, in converting long shaft to short shaft you need a shorter water tube, check; a shorter drive shaft, check; AND a shorter shift rod. With these parts the conversion is easy.

All the best,
J

I must assume that you have had a problem running a 20" engine on a 15" transom. I have that set up with my 75 9.9 and it operates just fine and not as you have said " It is extremely dangerous!!! It my not be the "desired" set-up but works for me.

 

[JDusza]

Re: 1977 9.9 johnson

I wouldn't do it and I wouldn't recommend it.
Peace, out.
J

 

[wrmdunker]

Re: 1977 9.9 johnson

Well our 2012 season is over and the boat is put away. Had a lot of outings with it and just needed to say that the boat and motor are an awesome combination. Very stable even with 3 adults at WOT.

 

[Rick.]

Re: 1977 9.9 johnson

That's great news. Sounds like you got a good outfit. Rick.