OMC Hydro assist to Mechanical shift conversion question.

[Metalwizard23]

I am converting my 1979 omc 250hp from hydro assist to mechanical shift.

I thought that it was an easy swap.. but I was just told by someone that I need a "Shift assist module"

I have done some searching.. and found a good wiring diagram..

a shift converter with the switches for it..

and a FEW DIFFERENT modules..

So my big question is.. Do I NEED this??? (what does it really do...) why wont it shift without it??

and How do I know which module I need... or are they all pretty much similar..

the engine is 351W with points and a standard coil so looking at the wiring diagram. it appears that it just hooks into the wires going to the coil... then connects to the shift controller..

any insight would be greatly appreciated! thanks

 

[Scott Danforth]

yes you need it.

it momentarily interrupts the ignition to make the motor stumble so you can get the dog-gears to shift..... without it, you run the risk of running people over as you cant get the boat out of gear.

as to which module you need. you would need to get the ESA that matches the drive you installed.

 

[Metalwizard23]

Ok I guess thats the hard part...

I bought a rebuilt drive from a reputable rebuilder I told them what engine etc I had and he built me the right one.. so im not sure EXACTLY what it is

the tag on it say 333857 d3 5.0 L V8

any suggestion for the module??

Heres my BEST GUESS.. does this one look correct...

https://www.ebay.com/itm/Shift-Assi...r-OMC-Stringer-8-Cylinder-Points/231704099608

I imagine the Shift controller switches are pretty much standard. looks like they are just a switch on each end of the throw..


thanks for the help..

 

[Metalwizard23]

Oh I guess thats the part number for the lower.. The full drive the only thing I know is its an OMC 800 low profile. 1979 ish LOL

thanks again!

 

[Redrig]

I am actually going to be converting to a mechanical soon as well and have most of the parts already.

yeah you need the ESA as Scott mentioned . otherwise you will not be able to shift out of gear when in the water .

converting from a hydro , really the only thing you need to different is the new converter with switches and you will need to wire in an ESA module . its only 2 wires , grey and purple.

purple goes from switched 12v source to the ESA

grey goes from negative side of coil to the ESA and a ground is spliced in there as well .

my understanding is that there are different ESAs for 4, 6 , and 8 cylinder engines , and an 8 cylinder engine ESA is black.

that link on Ebay is for a newer ESA and aftermarket. Are you still running points ? or do you have a electronic ignition , that will determine the ESA you need

 

[Metalwizard23]

THanks REDIG mine is all stock... its a V8 with points.
I saw the wiring diagram. it looks pretty straight forward.. purple wire to coil positive.. grey to coil negative..

I had been thinking of upgrading to Electronic ignition. sounds like thats a no good idea though with this..

 

[Metalwizard23]

Sorry one more thing... the one I LINKED say its OMC v8 POINTS so im guessing it will work...

 

[jbcurt00]

Metalwizard23 get in the habit of looking to see when a topic was started and when its Original Poster last posted a reply to that topic.

Avoid posting to old inactive topics, like the disconnect OMC ESA topic you subscribed to. Its been inactive for 14yrs, unlikely to have any new updates to be notified via your subscription to it.

That topic is now closed.

After 90+ days w no new posts from whoever started a topic (the Original Poster, or OP) dont post to the topic. It is considered inactive until the OP posts to it again.

This is all covered in the rules you agreed to when you joined. Theres a link to the forum help topics below in my signature. The rules are found there as well.

thanks for your cooperation and good luck w your OMC swap

 

[Metalwizard23]

Metalwizard23 get in the habit of looking to see when a topic was started and when its Original Poster last posted a reply to that topic.

Avoid posting to old inactive topics, like the disconnect OMC ESA topic you subscribed to. Its been inactive for 14yrs, unlikely to have any new updates to be notified via your subscription to it.

That topic is now closed.

After 90+ days w no new posts from whoever started a topic (the Original Poster, or OP) dont post to the topic. It is considered inactive until the OP posts to it again.

This is all covered in the rules you agreed to when you joined. Theres a link to the forum help topics below in my signature. The rules are found there as well.

thanks for your cooperation and good luck w your OMC swap

WEll im sorry then.. im used to forums where they yell at you "WELL WHY DIDNT YOU DO A SEARCH FIRST theres 20 other threads about the same topic"

So I did a search found the same topic and commented on that.. my mistake..

 

[Metalwizard23]

OK got it all together..

Got the ESA in and working (yes the RPM does DROP when I shift)

But I still have a HELL of a grind when I shift into gear..

not just a clunk but a grind..

Engine RPM at idle is 600 rpm ish..

im really getting frustrated.

Im uploading a video now.. its pretty big so it might take a bit before its live!


https://youtu.be/5hiIJAVjeG8

 

[Lou C]

Ok can't see your vid and I am not familiar with the Stringer mechanical only the Cobra, but assuming there are some similarities...
grinding is usually due to:
shifting into gear too slowly (shift briskly as the manual says)
mis-adjusted shift linkage where you are not getting enough travel into either FWD, or REV on either side of neutral.
rusted, sticky shift cable that does not move freely enough

all here I can contribute is my Cobra knowledge...
the Cobra used a 2 cable system, one cable goes from the remote control on the boat, to the engine shifter bellcrank
the other cable goes from the engine shifter bellcrank, to the lower unit (Via the bellcrank in the pivot housing). Both cables have to be adjusted to allow you to have equal throw on either side of neutral or else it will usually go into one gear fine and grind going into the other. On the Cobra first you adjust the transom shift cable then the remote cable. Not sure if the stringer is the same, but go over your adjustments, do not take any shortcuts or assume that something is OK when its not been checked, etc.

When I did mine I started with the drive off, adjusted the shift rod in the lower unit as per spec. Then adjusted the transom shift cable after checking drag on the shift cable with a spring scale (less than 2lbs). Tried it and it shifted OK into one gear but grinded into the other. Found that I had to also adjust the remote cable, was not getting full throw in the gear that had the grinding problem.

 

[Lou C]

And as far as the ESA, or shift assist, it is supposed to engage ONLY when shifting from in-gear to neutral with a load on the prop, as in the water. On the water hose on land it should not engage. If it engages when you shift into gear, then your shift cables or remote control is stiff and/or your adjustments are off.

About the points distributor, I'd keep it since the ESA you have works with it. If you change to an electronic unit then you will need a different ESA. You can contact CDI Electronics in Alabama they know how to deal with these issues and make aftermarket ESA units, I got one from them when my original failed after 28 years and there was not an appropriate OE replacement available....

 

[Metalwizard23]

Ok can't see your vid and I am not familiar with the Stringer mechanical only the Cobra, but assuming there are some similarities...
grinding is usually due to:
shifting into gear too slowly (shift briskly as the manual says)
mis-adjusted shift linkage where you are not getting enough travel into either FWD, or REV on either side of neutral.
rusted, sticky shift cable that does not move freely enough

all here I can contribute is my Cobra knowledge...
the Cobra used a 2 cable system, one cable goes from the remote control on the boat, to the engine shifter bellcrank
the other cable goes from the engine shifter bellcrank, to the lower unit (Via the bellcrank in the pivot housing). Both cables have to be adjusted to allow you to have equal throw on either side of neutral or else it will usually go into one gear fine and grind going into the other. On the Cobra first you adjust the transom shift cable then the remote cable. Not sure if the stringer is the same, but go over your adjustments, do not take any shortcuts or assume that something is OK when its not been checked, etc.

When I did mine I started with the drive off, adjusted the shift rod in the lower unit as per spec. Then adjusted the transom shift cable after checking drag on the shift cable with a spring scale (less than 2lbs). Tried it and it shifted OK into one gear but grinded into the other. Found that I had to also adjust the remote cable, was not getting full throw in the gear that had the grinding problem.

the video is live now..

On the 800 I have the shift cables adjusted where I think they are correct. CENTERED in neutral.. centered on the Shift control.. both throw the same amount each direction.. in the vcideo im going from forward to neutral to reverse to neutral to forward.. etc..

NOW the THROW from the "REMOTE" to the SHIFT CONTROL.. might not be ENOUGH but I dont see a wat to change that..

as for the ESA I bought one from the place you mentioned... it says it works with points AND you can upgrade to electronics ign.. but thats for later..

 

[Metalwizard23]

OK one more thing.. im at the helm so its hard to be at the helm at the engine and at the drive when I shift BUT when I PUSH the BUTTON on the shift control. the engine RPM does drop about 50%.. and it seems that the botton is getting depressed when I shift it.. so I BELIEVE its working correctly..

I have a friend going to come over tomorrow and take a look and give me an extra hand... id have mu daughter that filmed it help but it was hard enough to get her to do that LOL

thanks!

 

[Redrig]

Try unhooking the cable from the remote control from the shift converter and then fire it up and just shift it with your hand , see if stops the grinding .

 

[Metalwizard23]

Try unhooking the cable from the remote control from the shift converter and then fire it up and just shift it with your hand , see if stops the grinding .

Sounds like a good idea..

anyone know how far that cable from the remote should travel?? theres markings on the controller Diamond being center etc... how far should that actually travel?? i imagine it has to go at least far enough to engage the second switch for the esa... Im guessing that tells the Module "hey im in gear already you can stop now)

 

[kenny nunez]

3” of travel is the most the control will throw. Use the outer mounting point. I have never done a conversion like you have so I will not be much help. There is a detent feature built into the control so that the drive is fully engaged before the throttle advances. It is hard to describe the action, you just have to play with it and you will figure it out.

 

[Lou C]

ok this is coming back to me...there is a member on here user name of Boomyal...or similar and I think I remember him writing that he had done this conversion....might try pm'ing him and see if he is still around....

 

[Redrig]

one random thought ....... Are you using the same controller from your Hydro? Does a hydro controller have less throw than a mechanical ?

 

[Metalwizard23]

one random thought ....... Are you using the same controller from your Hydro? Does a hydro controller have less throw than a mechanical ?

YEs I am.. and I dont know how much the mechanical would have.. so I am going to look into that..

Yes that did cross my mind today to.. unfortunately its raining so its covered.. when it dries up I'll take a look.

Leaving for the elk hunt in a couple days.. so it might be next week..