Alternative to the Thunderbolt IV Ignition system

S

seachunk2

Member
Joined
Apr 16, 2006
RO Number
20886
Messages
131
I've done all the troubleshoot and testing possible and I've unfortunately had to conclude that the cause of my no spark/no start situation is due to a failed distributor module. The current engine is a 1995 Mercruiser 4.3LX. Mounted on the distributor is the module. from what I've read, it rarely goes bad. I guess I'm the "lucky" winner. This part is hard to find and very expensive. It might cost a few bucks more but I'm considering switching from the Thunderbolt IV system to an alternative. Anyone make this conversion and has a recommendation for me? Thanks1
 
Can't speak to theMerc 4.3L's, but I had these Delco Voyager EST kits installed in place of the troublesome & worn original points distributors on my old '88 Crusader 5.7 carbed engines. Never had a single distributor problem with those engines the 8 yrs I still had them after that Voyager kit install. Excellent distributors, plus matched coils and cables. I was not the actual installer, so I can't say just what is involved with wiring but the installation instructions( "7 easy steps" ) for them are available online .
They were highly recommended to me by the Crusader factory techs & worth every penny & more .

MichiganMotorz has them for the 4.3L (Item 107-B, $269/ in stock) and other GM engines.

Here is the description from Michiganmotorz.:

"Genuine 4.3L GM Delco Voyager EST marine electronic distributor kit. Made for ALL 4.3L marine engines made from 1985-current. This is an excellent replacement kit for "points" distributors and faulty MerCruiser Thunderbolt ignition systems. This kit is U.S Coast Guard Approved and has the official marine SAE J1171 stamp on the bottom of the distributor. This is the EXACT kit that Volvo Penta, OMC, Marine Power, etc use on their 4.3L marine engines. 100% compatible and operational with ALL Mercruiser 4.3L marine engines.

This kit includes:

•4.3L Voyager electronic distributor
•Coil with bracket
•Spark plug wires
•Wire retainers
•Timing shunt
•Pig-tail plug
•Coil-to-distributor wire
•Easy to follow, 7-step installation instructions"

I think Marineengineparts may have them also.
 
Thanks for the reply Sandy. I'm seriously considering the Delco Voyager. I wasn't planning on a boat project this summer since I had plenty of other things planned but boating was part of that plan so it looks like I don't have much choice. If I were able to get hold of the module at a reasonable price, I could be up and running in about 10 minutes since all that's involved is two mounts screws and plugging in the harness. I'm going to keep looking for the needed module but if I can't find one I see myself ordering the Voyager kit very soon.
 
I would suggest looking at the DUI (Davis Unified Ignition). You end up with a plug in play new distributor, electronic module with the right curves and the coil all in one unit.

On my big blocks I had to replace both Thunderbolt trigger modules two years ago. Then I lost a coil. And finally the other engine lost the Thunderbolt module.

Installed a DUI and compared to the other engine with the old Thunderbolt it is perfect.
 
Hi all. I'm the OP. It turns out that replacing the sensor and the coil with ALL BRAND NEW PARTS worked out. After all this running around it was never the module. I'm not complaining at all. I'm not sure if the first sensor I put in was defective or if the "used" coil I was relying on was the culprit or was it both???? Anyways, I'm going fishing tomorrow. Thanks for all the advice!
 
Seachunk2;

The Sensor you're speaking of... This is the part that fits in the distributor with a slot that the rotor disc runs in, correct? Mercury Part # 87-892150K02? It has 3 wires coming off it that plug into the ignition wire harness?

The reason I ask is because I've run into a partial ignition failure and everyone seems to point me to this part as one of the first to change (after a new cap, rotor, plugs, and wires). Thinking that it's probably worth picking up this part and a new coil, especially since it worked so well for your situation!

Adam
 
Buffo, yes that part is called the sensor. I replaced it with a new one. I also installed a new coil. The engine started. I was happy! Don't use an old coil. Buy a new one. The sensor and coil will run $50 or so (Aftermarket brand like Sierra).
 
is this the pick up coil in the distributor you're talking about?
 
You must log in or register to reply here.
Back
Top