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omc stringer electric shift problems

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glenn_1

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Hi, i am new to this, but i am hoping that someone can help me. I have a 1977 stringer stern drive, electric shift. I had the upper gear case rebuilt last year and everything was working perfect until yesterday. I was cruising along, as normal, and all of a sudden the motor started to rev up and it seemed to be acting the same as last summer when the upper gear case went, but now i still have reverse gear. It still shifts into forward gear and the boat will still move but only while idling. As soon as i give it some throttle(1000 rpm or more) it seems like it is slipping. would anyone out there know what could possibly cause this and point me in the right direction of what to look for.

Cheers

Glenn
 
cross your fingers, Glenn...

sounds like you spun a prop hub.

try a new or spare prop, and don't let anyone tell you the old pin type props don't have a friction hub, because they do

the rubber rots with age and the hub slips
 
my first thing would be like hystat said prop hub my second conclusion might be the internal shaft hub with spring which is inside of lower unit a manual will help you alot on these electric shift the lower unit are easey rebuilds once you do your first one but you deff need a manual are a break down schematic of lower unit, you have two magnets in your lower assembly 1 is forward and one is reverse when they are energized they expaned to force a spring against the gear you are in which makes your boat go, if your forward magnet is week are your spring is weak are broke it can cause the same situation,, but start with prop hub first chances are that is your fix
 
How about this:

Place a board(s) between the prop and the under side of the anti-cavitaion plate.

Put a socket on a breaker bar and put some torque on the prop nut.

If it's a spun hub, then wouldn't the prop nut/prop shaft turn and the prop won't?
 
Does the nose cone thread onto the prop shaft, like on the old Chryslers?

If so, get two nuts of the same thread and lock them together on the prop shaft, then use the breaker on it.

(But, I have no knowledge of the stinger prop nose arrangement.)
 
i replied to your pm, and yes i think like Hy pray it's the prop , but as i said in the pm if you started to over heat when it happened then it's the coupler.

It happened to me first the splines went in the upper then the week after i fixed that the splines went in the coupler, then the week after the prop spun.
 
i checked the prop first, but it seems fine. I clamped the prop in the vice and put a long screwdriver through the pin holes and heaved but nothing moved. I did not overheat this time, but it did last year when the upper went. I had to replace the main shaft, that also runs the water pump, seals and all new bearings. i have the lower unit off now and i am taking it apart in the garage. i do have a manual and i am now removing the the big retainer clip and about to take out the reverse gear. I haven't seen anything yet that seems worn. But i can turn the upper shaft and the prop shaft will turn with it until i hold it. is this normal, or do i have to go deeper??
I really appreciate all the help
Glenn
 
yes normal, dont get scared when you pull the prop shaft out cause alot of bearing will uselly fall down into houseing just make sure you have a can or tube of grease cause you will need it to hold bearings in place, oops i said prop shaft but its the water pump shaft the vertical shaft in lower drive, check your forward hub and spring and see if your forward magnet might have spun alittle to far and cut or grounded the wire just a tad
 
well, i have most of the lower unit apart. I have the reverse coil out and the reading is 5.7 ohms( which is a good reading according to the manual) but the wire was frayed very close to the coil and looked like it may have been shorting out, but according to the manual this is the reverse coil. The forward coil is still in the housing as i need to get a loan of a wrench to take the big nut off the end of the vertical shaft. I did check the forward coil and the reading is also good, but i don`t have it removed to inspect it yet. all the gears and the shaft splines look good but i am not an expert. how do i check the clutch mechanism? i am going to check the hub and the spring tomorrow.

thanks
Glenn
 
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i tried the prop again by clamping the part that the pin slides through in the vice and both my buddy and i grabbed a blade each and tried to turn the prop. it did not budge, but again, i am no expert.

nothing ventured is nothing gained.

Glenn
 
glenn_1 said:
i tried the prop again by clamping the part that the pin slides through in the vice and both my buddy and i grabbed a blade each and tried to turn the prop. it did not budge,
Click to expand...

ahh..
sounds like the prop is ok. That's a much more valid test- if it held with the leverage at the blades and two guys... probably not the hub.

did you have Type C lube in the lower unit?
 
if you have not taken the forward hub assemby out yet , take you a battery charger hook the ground to your case touch the forward magnet wire to the positive clamp of battery charger for a second you should here a nice solid clck, this tells you the hub asembly is locking into gear if no click that tels you the spring is broke
 
i am not sure of the type of oil that was put in the lower unit. all new lube was put into it last October when the upper gear case was serviced, but i do recall the mechanic saying something about a different lube because of it being electric shift. I will try the forward coil in the morning with the battery charger. Hopefully i will find something tomorrow. I am also going to order a new seal kit for the lower unit.

I can't thank everyone enough for the advice. These forums are awesome!

cheers
Glenn
 
yea, i am sure it was type c premium blend blend that they put in at the omc dealer. i put the prop shaft and the reverse coil back into the housing again to test the coils. i put power on the reverse coil and i can hear a distinct click when it locks in and a click when the power is removed and it is disengaged. the prop shaft is definitely locked in with the vertical shaft as i can hold one and not spin the other. I then put power to the forward coil and i can hear a faint click when it engages but not when it disengages. i have to spin a shaft or shake the housing in order to get it to click again, but it seems to be locking into gear when i hold one shaft and try to spin the other. is this normal? except for not hearing a good sounding click, it seems to be fine. i don't want to strip the gear case any more if i don't have to. any ideas or advice? maybe i am looking in the wrong place. coupler????
 
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that click should sound like the reverse click you should here it click out to, if it was me since i had it that far i would have went ahead and took the rest apart but thats me, when i had my boat i kept a spare and since my dad worked for omc untill he retired in 79 i had a manual and someone that taught me the electric shift rebuild, i still help walk friends through the rebuild but i can no longer do them since ivebeen disabled, they were a very easey drive to work on and if taken care of very dependeble
 
if the coupler was bad, no reverse no forward and it would do the same thing in reverse now i have seen the press on ball gears spin on shaft 1 way but not the other but you would have felt like your whole bottom of boat was being torn out,at this point i would say the front hub assembly and or magnet grounded or weak and like your kids say you can do it dont rush lay everything out in order for reassemby
 
ok here is something new. i was just down talking to the dealer to pick his brain, the first thing that he said was a spun prop. i told him the way that i checked the prop and he said that was fine, but.........he told me to wet the prop and try it because of the water lubricating the rubber might make it slip under load. so i just soaked the prop in my barrel for a few minutes and put it in the vice again. this time i can make it move myself with a little muscle behind it.... is this supposed to move at all. he told me that where i didn't let it spin up very much , that the rubber was still grabbing the sleeve a bit but would sli[p under load. should i put the drive back together and buy a prop???
Glenn
 
Glenn,

I had the same problem several years ago. The prop seemed like it would slip, only in forward. I ended up pulling the prop and rehubbing it. The problem persisted though.

After further troubleshooting I found that the switch in the throttle control box was the problem. When shifted into forward the voltage to the electric shift would jump from 12 volts to 0 volts as I slowly moved the throttle.

I found that this switch was very expensive. I ended up installing my own switch and eliminated the original switch. The new switch I picked up from a autoparts store with a weather protection boot on it. The switch is a 3 position on-off-on switch. You wire power to the middle lead and then forward and reverse to the other two. The on-off-on positions is very important so that you can not engage both shift coils at the same time.

I hope this helps. Look forward to see how it turns out for you.
 
thanks guys, my seal kit will be here wednesday morning and i found a prop. I am hoping to have her back in the water thursday to try her. i will keep you posted.
again, i want to thank all of you for the advice and tips. i think i would have been less confident without this forum. i am sure to be on here more in the future.

Glenn Sinclair
 
glen dont throw your old prop way on each side of prop drill you a hole 3/8ths go to hardware store buy a 3/8ths aluminum rod and some epoxy cut you two pcs to put in holes roughly 3/4 inch long make sure you put the epoxy on the aluminum pins then insert in hole let dry for 24 hrs you have a emergency prop just in case you get stuck out on water with it but dont use with wide open throttle its just a putt putt back to shore prop
 
i drilled and tapped(fine thread) 3 holes and put three 1/4 fine thread stainless steel bolts in the prop. the bolts go through the prop housing, the rubber, and screw into the brass insert in the center. i used silicone on the bolts but maybe the epoxy would be better. i spaced them exactly the same behind the fins, but this is just a quick fix so that i can get back out on the water this weekend. i would really appreciate getting that prop from you, as i don,t really want to use this prop as my main, but maybe a spare.
 
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