Engine swap Force to Mercury

[Bsarv]

Can someone shed some light on this subject for me? I've looked high and low for answers but my questions are somewhat specific.

My transom went south on my current boat, but the boat has a good 1984 115hp Mercury "Tower of Power" that has recently been gone through.

So I picked up a 1992 Quantum bass boat cheap with the intention of swapping the engines as it currently has a non running 1992 Force 90 HP on it.

I am mechanically inclined so is this something I can really do myself?

Does anyone have any good advice for me? My Merc just had new controls put on it and I understand I will move those over with the engine. What else needs to be done? It can't be that simple to just swap motor and controls over? Is there any other electrical components that need to be moved?

I measured the transom height and everything so I believe it should work. I do know from some rough measurements it looks like the bottom bolt holes will line up but not the top.

I would like to see a video of a swap but I couldnt seem to find one.

Anyone else have experience swapping an engine on a Quantum or Bayliner? Just as a side note the Force is pre- mercury.

 

[Chris1956]

Re: Engine swap Force to Mercury

The swap should be real easy. Move the throttle, shift and electrical cables over with the motor. You can change the fuel connector to a Merc. The steering should bolt up as well.

That TOP is very likely a Longshaft (20") motor. I presume the Force is as well.

 

[ezmobee]

Re: Engine swap Force to Mercury

As Chris said, it really is that easy. I'd just add, it's generally much easier to make your disconnections from the motor end as opposed to the control box end. Any gauges that may have been added could add some slight complication.

 

[Bsarv]

Re: Engine swap Force to Mercury

Thanks for the quick responses guys, I am always a little hesitant to dive off into the unknown.......

It does sound relatively easy so I think that's what was concerning me the most. Looks like I have an engine swap in my future.........

The TOP is a long shaft motor

 

[Frank Acampora]

Re: Engine swap Force to Mercury

It may be even simpler: Mercury made late model Force engines and used Merc controls and ignitions. IF--If the 92 has Mercury controls, then you don't even need to swap them. Simply mount the engine on the transom. Of course, you will need to drill new mounting holes.

AND--Please-- Check into why the Force is not running. These engines are simple to diagnose and simple to repair.

 

[roscoe]

Re: Engine swap Force to Mercury

Anyone else have experience swapping an engine on a Quantum or Bayliner? Just as a side note the Force is pre- mercury.

The Force, if indeed a '92 90hp, is not pre-Merc. It is Merc.

 

[Bsarv]

Re: Engine swap Force to Mercury

I wasn't sure if the force was actually considered a merc or not as I thought it was mid year 92 when they started...... It is titled as a 92 and the sn# shows its a 92 but it has US Marine controls.

Frank -the force actually runs I bought the boat from an individual that inherited it from his father.

The guy used it for a year then one day it wouldn't start he thought maybe a wire had shorted because the starting side of the battery wouldnt work so he parked it and that's where it sat for 2 or more years until he sold it to me.

I got the boat home and started looking around and the battery terminal has simply come undone.

I fixed that threw a battery in it and it turned over and acted like it would run. So I cleaned the carbs (didn't rebuild) replaced all of the fuel lines from the tank to the motor, also had to clean out the tank and replace the pickup line and filter then replaced the sending unit. Finally I put new plugs a new (used) fuel pump on it as the other one was in very bad shape when I took it apart.

The boat runs and will idle somewhat decent then when put in gear it dies, I've run a compression test on it all cylinders came back equal or close to it a little low but probably because it sat and it could use a round of deep creep.

Soon as I try to put it in gear it will die.... I don't know enough abou OB to know what to do I feel like I've already invested enough time and effort although I hate to give up. In looking at the motor itself cosmetically and under the cowl it looks very very clean I can't see much wear on the engine at all. So I know it has potential but where do I draw the line? Remember I bought a "non" running boat with the intentions of putting my Merc 115 on it.

So if I can be fixed for a reasonable amount then I wouldn't mind doing it.

I feel like I've done all I can my next step would be a shop, I just need someone to let me know if its worth investing in or not without breaking the bank.........

Alot of folks I talk to have a vendetta against Force Anyway so it's hard to get a true honest opinion. The common response I get is ditch the force and go with the merc.

For simplicity if I can get the force going I would be fine with that. I just need a good fishing rig......

Thanks to all for the input, this is an excellent site, I've read hundreds of threads on here and just now finally signed up.

 

[jsimms724]

Re: Engine swap Force to Mercury

I dont think you specified what kind of hull the transom went bad on. Just thinking there may be a new prop in your future, my 2 cents

 

[Frank Acampora]

Re: Engine swap Force to Mercury



Well, if it has a US marine control box then it most likely has Chrysler/Force control cables and Mercury ignition adapted to Force (by the manufacturer.)

Mercury cables will not fit on the engine and vice-versa so if you do swap engines you will need to swap control boxes and wiring also.

NOW: As to the Force--If it has decent compression, starts, and idles somewhat you are more than halfway there. Stalling at idle is most commonly due to fouled plugs but you have replaced them already so we can rule this out. If the idle is too low, the engine will reliably stall when put into gesar, especially forward because there is more load there than in reverse. SO, if the boat has a tachometer set the idle speed to 700-750 in the water, in forward gear. If you do not have a tach, try to borrow one of the tiny tach types or a timing light with a tach.

Set timing to 28 degrees static at wide open throttle--this translates to 30 degrees BTDC at Wide Open Throttle. Do this before changing the idle speed.

Idle speed is adjusted using the idle stop screw on the timing tower. The three photos are from different sized engines but you can see that the adjusting screw is in the same place.

Given what you have posted about the engine, you should get it running with almost no more money invested and just a bit more time.


BTW: The Force 90 will get you there and back, but if it is all-out top speed you are looking for, then the Merc is the choice.
Go over to the Force forum and read the sticky FAQs: synchronizing timing and carbs.

 

[Bsarv]

Re: Engine swap Force to Mercury

Frank - thanks again for all of the input you have been very helpful. I won't have a chance to tinker with it until this weekend....

I am sure I will have more questions as I get further into this so I'll be in touch.

Again thanks to everyone on here.

 

[Bsarv]

Re: Engine swap Force to Mercury

I know it has been awhile but I have been busy, I have a lot of updates and was hoping to get a few more questions answered.

Since my last post I've had all three carbs rebuilt completely, rebuilt fuel pump, installed a water separator, replaced impeller and fresh oil in the lower unit.

The engine is running as it should now and the last compression test readings were great. 150 - 155 in all three cylinders.

Now it seems that the engine isn't getting enough fuel?

It will run fine then I will slowly see the fuel filter empty out then I'll have to pump the bulb up. Sometimes the bulb goes flat and stays flat just from simply squeezing it by hand.

I've read so many posts about bad bulbs my eyes are crossed, I replaced the bulb with a cheapie from WM when I first bought the boat. I've literally replaced every component fuel related on the boat.

To preface this I've cleaned the fuel tank twice, double checked the pickup tube verified its clear, triple checked the vent for obstructions, tried running with the fuel cap loose, there is no check valve, replaced every bit of fuel line from engine to tank.

I took the line from the fuel pump to the carbs off and put it in a coffee can while someone hit the key. It pumped a decent amount of fuel out and seems to be somewhat steady. It wasn't fantastic but it seemed sufficient.

Does anyone know the amount of fuel expected out of the fuel pump?

Is it possible that the primer bulb is bad and causing me all these headaches?

Thanks.

 

[Frank Acampora]

Re: Engine swap Force to Mercury

Checking fuel delivery at cranking speed shows nothing. The pump usually runs from about 2 PSI to 6 PSI and only at full throttle, where the engine is using the most gas, will you see if it is insufficient.

Yes, a bad primer bulb can cause this BUT more likely, since your bulb is being sucked flat, the fuel pump is good and the problem is before the bulb.

If there is a quick-connect fitting in the line, check both male and female fittings for partial clogs. Don't just look at them, remove them from the fuel line and fish around inside with a fine wire..

Borrow a second 3 or 6 gallon tank and check the engine performance when attached to that one.

 

[Bsarv]

Re: Engine swap Force to Mercury

Frank ? thanks for all of your input I really appreciate your help and advice, this is an awesome forum.

So I took the boat out last night with my newly installed name brand primer bulb, I was able to keep fuel to the motor then all of a sudden it would get plugged up again so I checked all fittings and hoses and came to the conclusion that there has to be something getting caught in the pickup tube intermittently.

It will be fine for a little bit then I guess the sloshing around whatever it is will eventually make its way back to the pickup tube and plug it up again, only way to free it up is crack open the line at the fitting and let the fuel drain back into the tank and free the blockage. So looks like another tank cleaning for me!!!!

So now that I was able to run it for a decent amount of time I was able to get it off the trailer and run around the lake, the boat runs but wasn?t running well @ WOT it was very sluggish and really ran very poorly. I don?t understand it almost acts as if it isn?t hitting on all cylinders??

I loaded the boat up as it was getting dark in looking at the engine I noticed when I had the boat at WOT the carbs weren?t even coming close to being opened all the way up. So right or wrong I put it in gear/WOT (the motor was off of course) I took the link with the ball bearing ends on it off and drew it out to where it would actually have the carbs at WOT when in gear/WOT. Basically I guess I synced it up when doing so after I adjusted the ball bearing link out the idle was set way high of course so I adjusted the idle/timing screw to where the line on was lined up with the roller. Sorry for not using proper terminology as I am not sure what a lot of these small parts are actually called, so I hope this is making sense.

So I decided to put it back in the water for one more test run with my new adjustments, WOW is all I can say??.. it ran better than I?ve ever see it run since I?ve owned and started on this journey starts right up, runs and idles smooth and has a very nice acceleration planes out very nicely and quick too. I only ran it for a minute or two as it was getting too dark.

So my next question is I?ve read a lot about detonating and or a meltdown if the timing is advanced too far, my adjustments shouldn?t have changed the timing right? After all I have been through with this boat I would really hate to mess it up now.

I plan on getting a tach installed as it doesn?t have one installed now, also going to look for a timing light, although I don?t know how it would?ve gotten off, moved or out of time as I?ve never touched the timing.

I am hesitant to run it too much until I figure out if just adjusting the idle/timing screw to sync the engine up had any effect on the engine timing or advancing it too much.

I am getting so close and again appreciate all of the positive input and answers to my questions, this poor thread has morphed into a Frankenstein thread I have went in every direction with it. LOL but I am almost there! Thanks a million.