Force 85hp questions

[myboatisbroke]

I have a 1989 Force 85 hp with the Prestolite ignition system and a bad powerhead. I have the opportunity to get a 1984 Force 85hp with the Motorola distributer ignition system. The 84 has a good powerhead, but no spark. Can I swap my Prestolite ignition onto the older motor? What are the common issues with the motorola system, and how expensive are parts? I dont have the money to rebuild my powerhead, and just want to use my boat for once!!! Its my first "real" boat other than a duck boat and seem to think boat stands for Bust Out Another Thousand!!!

 

[jerryjerry05]

Re: Force 85hp questions

One system will work on the other.I don't think you need to modify anything to change it over.
The Motorola system parts can be found.e-bay is a good bet.
Change it over.Make sure the timing is set right.Get a FACTORY manual the others don't give the best info.J

 

[Frank Acampora]

Re: Force 85hp questions

Nothing between the two systems is swappable! The whole ignition system must be changed.

If you want to swap Prestolite onto a Motorola distributor block, you will need to drill the top of the block for the 5 screws that secure the alternator mount. Then you must make a spacer between the mount and the top bearing so the crank does not ride up in the block. Because the top of the distributor block is machined higher, the top seal will ride higher on the crank and and you may need to press it lower in the alternator mount.

It is not a difficult job if you are handy and patient, but it would be better to buy the components for the existing Motorola system.

Before going wild, check the usual reasons for no spark. The Motorols system MUST be powered from the switch--it is not self energising like the Prestolite and the switch is wired differently. Blue wre is attached to "I" and provides power to the distributor electric eye and the CD box. White is a 12 pole tach signal wire.

 

[myboatisbroke]

Re: Force 85hp questions

Nothing between the two systems is swappable! The whole ignition system must be changed.

If you want to swap Prestolite onto a Motorola distributor block, you will need to drill the top of the block for the 5 screws that secure the alternator mount. Then you must make a spacer between the mount and the top bearing so the crank does not ride up in the block. Because the top of the distributor block is machined higher, the top seal will ride higher on the crank and and you may need to press it lower in the alternator mount.

It is not a difficult job if you are handy and patient, but it would be better to buy the components for the existing Motorola system.

Before going wild, check the usual reasons for no spark. The Motorols system MUST be powered from the switch--it is not self energising like the Prestolite and the switch is wired differently. Blue wre is attached to "I" and provides power to the distributor electric eye and the CD box. White is a 12 pole tach signal wire.

yeah, I planned on swapping everything over, mainly because most of the ignition components in the prestolite system were replaced by the previous owner, but if the motorola system is as simple as it sounds, it shouldn't be that big of an issue. I am a Agricultural equipment and diesel mechanic for a living, and am pretty confident doing this. The biggest thing I was worried about was the cranks being different at the ends to allow for a different flywheel.


I appreciate the responses, and I'll let you know how I make out

Thanks!!!

 

[Dustin099]

Re: Force 85hp questions

Nothing between the two systems is swappable! The whole ignition system must be changed.

If you want to swap Prestolite onto a Motorola distributor block, you will need to drill the top of the block for the 5 screws that secure the alternator mount. Then you must make a spacer between the mount and the top bearing so the crank does not ride up in the block. Because the top of the distributor block is machined higher, the top seal will ride higher on the crank and and you may need to press it lower in the alternator mount.

It is not a difficult job if you are handy and patient, but it would be better to buy the components for the existing Motorola system.

Before going wild, check the usual reasons for no spark. The Motorols system MUST be powered from the switch--it is not self energising like the Prestolite and the switch is wired differently. Blue wre is attached to "I" and provides power to the distributor electric eye and the CD box. White is a 12 pole tach signal wire.

You know your stuff on these force engines. I just replaced my impeller via your sticky.