[twoglasseyes]

I was wondering if any of you guys that do your own work on your outboards have ever run into anything like this. I have a 5hp seaking/john/evinrude 1956, but that isnt the problem. My buddy, doesnt know much at all about outboard motors just got a new 1957 12hp seaking. The motor runs perfect, and it waters good and has newer coils, so everthing on the top end is great. When we put it on my boat and launched it for a test run, everthing seemed fine unitll it slipped under higher rpm. It doesnt seem to slip in reverse, and in forward it hooks well enough to make it plane out, but once you open it up a little more it lets go, rpms go up and boat slows. I turn down the throttle and it hooks back up, and you can repeat the above untill it slips out again. I was wondering if there is a clutch in the drive somewhere in the drive shaft. My parents had an evinrude tri-hull v8 with an omc outdrive and it had a clutch that slipped out in the lower unit. We were able to switch it with the reverse clutch, since you never really go full throttle in reverse. I was hopeing that his might be the case. I'm picking up a manual today after work so that will probably help make things clearer. However, the only outdive I ever saw the inside of has been tha big omc. Any insights or tips would be appreciated.

 

[MrB]

I really would have to be there first hand but to me it seems like the high speed choke is not set properly. Not sure about a clutch tho, I have a 57 seahorse and it has a low speed and a hi speed choke. Also check out these sites there might be some more info there.

http://forums.iboats.com/

http://www.outboard-boat-motor-repair.com/Default.htm

 

[twoglasseyes]

Nice try, but its definatley not an engine issue. The chokes and air fuel mixes are all right. It runs perfect, but loses the connection between motor and propeller, somewhere in the driveline. :?

Thanks for the links!

 

[Rollcast]

Maybe a prop related to boat size issue.

Make sure its properly angled in the stern.

Try going to top speed slowly.
That lets the prop rpm catch up with the boat speed.
Too fast of acceleration will cause the prop to push the water away and choke on the air gap.
(The over rev of the motor).

On a different boat it might plane up quick and never over rev.

Worth a try at least to eliminate if its actually the motor.
Sounds like it runs great.

 

[BassCaster]

Is there a clutch?....If there is it's slipping..but without a shop manual it's all quess work..

 

[twoglasseyes]

Thanks for the guesses. I could only find manuals for the larger motors online in pdfs, and the larger old evin/johns have a cone type clutch that looks like its in the lower end, but couldnt find anyhting on the small ones. I just cant wait to get the manual tonight. Cant stop thinking about it. This motor is gonna be Fast when its ready. One thing I really like about it is it has the gas tank in the hood, self contained. Now all we have to do is put a fire extinguiser mount on it and its ready for deep. :lol:

 

[Gutterball]

Does the boat shake at all when the "slip" occurs? If there is any vibration or shakin you could have what people call a "spun" prop. It's when you burn the rubber torque housing on the shaft

 

[twoglasseyes]

Im gonna check that out as soon as I get the manual tonight. It does not shake. It just revs high, prop slows down, and boat settles down into the water. I tried like rollcast said when I was testing it out, and it doesnt help to gain speed slowly. It will still let go when you get to a certain point

 

[twoglasseyes]

The manual was less help than I thought it would be, but I think gutterball was right.
Question. Is the rubber tourque housing inside the prop, between the prop and shaft?
Thats the way the manual made it sound, but the illustrations werent all that helpful.

 

[Gutterball]

The rubber tourque housing should be inside the prop between the prop and the shaft. The ones i've dealt with are usually held on with a cotter pin or two and a nut

 

[twoglasseyes]

Cool. Thanks for the confirmation. Im glad its outside the housing in the prop, like I was thinkning. Before I found out where it was, I thought I was gonna be pulling the lower end apart. Not that that would have been that bad, but this is easier for sure!

 

[junglejim]

If it is a older motor it may have a shear pin. The shear pin can bind up under low rpm but when the rpm's are increased the shear pin slips not allowing the prop to spin properly. In newer motors with a rubber bushing in the prop hub will act the same way same way if if the rubber has spun in the prop. I am not sure if this (spun hub) can be fixed. If this is your problem check with a prop repair shop.