1987 125 hp force prop and lower unit swap questions

[lostinohio]

Bought boat earlier this spring from. 2nd owner. Runs great and I chipped the prop. Thats where I found out this motor is gonna be fun. Most everything is unavailable. It is a non thru exhaust prop 15 spline. What I have found is they do not offer a hub kit for this lower unit. After lots of calls I do have a prop on its way and will get my old one repaired for a spare. Question is has anyone been able to modify this lower unit or a hub kit to fit this? Other brainstorm has been can I swap this lower unit out to a more common output as to be able to use other props?

 

[Texasmark]

Lower unit is a bit pricy for a solution. Prop shops can do marvelous things with props. Merc uses a 15 spline LU in that HP range and 13-14" diameter props. That's all you need to get a new prop if you ask me.

Here's one possible solution: http://boatpropellers.iboats.com/Fo...19.00-Pitch_Propellers/877/?cart_id=837502592

This does indicate that the prop shaft takes a 15 splined hub. Other difference might be something unique about the hub to "thrust washer" interface, like the TW is too large in diameter to fit into the slot in the front of the prop, for those props that don't have a flush face. I had that problem with the thrust washer I had been using with a removable hub prop and went to a Laser II SS which had the rubber pressed in hub with a recessed inner diameter. The thrust washer was too large and the prop wouldn't go all the way in.

Simple solution; I went to a local boat dealer, near the water, been in business half a century, asked the question, he handed me a box (must have been 50 or so) of thrust washers, dug around and found one to fit inside my prop, gave him my old one and away I went. That was the same dealer I swapped for the Laser and he had shelves full of used props too.

 

[lostinohio]

This is not a mercury force. This was still chrysler. If you try to find this on the prop advisors there is nothing available. Local marina had no answers for me. Found a company that still had 3 old inventory props in stock and he said the prop kits won't work on this. Had me kind of stumped is why I'm here asking.

 

[lostinohio]

And the link you shared shows my issue. Those are not available

 

[The Force power]

This is not a mercury force. This was still chrysler. If you try to find this on the prop advisors there is nothing available. Local marina had no answers for me. Found a company that still had 3 old inventory props in stock and he said the prop kits won't work on this. Had me kind of stumped is why I'm here asking.

try this;


https://forums.iboats.com/forum/eng...ler-outboards/10926043-lots-on-chrysler-props

 

[lostinohio]

That person doesn't exist on ebay. Ive done my searching for props and have answered that question. Im more interested in thoughts on my original post

 

[Texasmark]

iboats prop search lists the engine and year model being only 3 years, '86, 7, and 8. One of you are wrong. I had an1971 85 Chrysler, in Seafoam White, but never had a reason to remove the prop. The OEM prop had a reverse curvature at the leading edge of the blades as they extended from the prop barrel. Sorry design as this reverse curvature caused a "cavitation" burn in that area about the size of a Us Dime coin, removing the paint and etching the aluminum.

Been too long but maybe it was held in place with a cotter pin as the prop nut was long and conical ....apparently it slid on and contained the "drive pin" meaning there was no splined shaft. Exhaust gasses on that engine emitted from the AV plate under side. If that is what you are after, Michigan wheel made a lot of props for a lot of engines over many, many decades. Might give them a try.

How about a side and both ends views of your current prop.

 

[lostinohio]

Knowing the story behind the force motors help understand the issue with parts today. Force was a us marine motor and was a partnership with chrysler and then Mercury took it over and made there changes. So unfortunately for me I am on the backend of the chrysler partnership. My new prop is scheduled for delivery tomorrow. I will take pictures of the lower unit and prop when I swap it. Im not sure if the fact they call this a L drive lower unit is what causes the issues.

 

[matt167]

Chrysler bought West Bend to create Chrysler marine, but sold the division to US Marine in 1984 because it was part of Lee Iacocca's re structuring which saved them

You mention L drive, which were only made for a few years. I think 1987-1992. and yup. Everything to do with that L drive is no longer available. The entire marine industry has forgotten about them. They are worse for parts than the 3.7L Mercruisers.

You will have to have your original prop sent out to be fixed, because yes, props are NLA.. I'd recomend selling the boat once you get it squared away.

 

[lostinohio]

I'm gonna run it and not sell it but I get where you're coming from. As said I've located a few props. For being 33 yrs old it is a low hour and a strong running motor. It has managed to stay un molested all these years from hack mechanics. Im guessing without looking to deep into it that I should be able to swap the lower unit with a later year model if needed. I figure I will run this till I can't anymore then either repower the boat or time to get a new one. That brings me back to why I asked if anyone has been able to modify a hub unit to work. If not I will see about acquiring a couple more spare parts.

 

[matt167]

Only L drive fits L drive. There is nothing else

 

[Texasmark]

Don't underestimate prop shops. James Propeller Service in Farmer's Branch, Texas used to do my props.

 

[lostinohio]

Got the prop I ordered in. Was rubbing a little. Got a new thrust washer from the marina and all is good. Now a nice day to go run it. I guess I will just get my old prop fixed and hope I don't destroy anything. Gonna keep my eye open for boats laying in yards and see if I can find an ol force I can pick up cheap and have some spare parts.

 

[matt167]

make sure it's an L drive if you get spare parts. The powerheads are the same as the outboards, but you can buy one of those all day long. It's everything below that which makes up the L drive that is impossible to find.

It's a very cool setup and it was almost revolutionary, but I believe it was abandoned due to Brunswick ( Mercury parent company ) buying Bayliner/ Force

 

[The Force power]

make sure it's an L drive if you get spare parts. The powerheads are the same as the outboards,

I'm curios to know if the power heads for the L-drives had the same crank in them as for the Jet-drives ?

 

[matt167]

I had to go back and refresh memory on L drives as its been a while. The crank is different from the outboards, something i had forgotten.. I looked at an L drive boat years ago. Bayliner Capri of some sort Iirc

 

[The Force power]

IF... the Crank is the same, then a power head from the outboard will not fit on the L-drive, either way parts for a L-drive are slim to none available by now(as you already mentioned)

 

[matt167]

well, I looked it up and they ARE different from outboard. They could even be different than the jet too. I completely forgot about the Force Sport Jet