Volvo Penta BB260 Ignition Coil

[JohnnyA561]

Question: I have twin 1987 Volvo Penta BB260, with Thunderbolt Ignitions
The boat is a 1987 Rampage, I'm the 3rd owner.
The boat runs ok, but the coils are looking worse for wear so I figured I would replace before they go, which would probably be at the worst time..
There are Resistors (look like 835999) that are not being used, and the coils that are on there now say "use without external resistor".
To make matters even more confusing there are 2 different coils:

1) Port engine has a NAPA 12v (No external resistor required) 905​

2) Starboard Engine has a 27270 (Use without External Resistor) 0700​

This one looks like it might be a Chevy Coil​

Obviously looks like one or more folks who should have NOT been touching this got their hands on it. They did some minor rewiring to bypass these resistors.
Can I safely go with a compatible SIERRA Coil with an internal resistor and be done with it?
If so can anyone recommend which one. I really would hate to have to go and un-wire the wire job they did unless I have to..
Thanks in Advance...

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www.volvopentastore.com

 

[Bondo]

Question: I have twin 1987 Volvo Penta BB260, with Thunderbolt Ignitions
The boat is a 1987 Rampage, I'm the 3rd owner.
The boat runs ok, but the coils are looking worse for wear so I figured I would replace before they go, which would probably be at the worst time..
There are Resistors (look like 835999) that are not being used, and the coils that are on there now say "use without external resistor".
To make matters even more confusing there are 2 different coils:

1) Port engine has a NAPA 12v (No external resistor required) 905​

2) Starboard Engine has a 27270 (Use without External Resistor) 0700​

This one looks like it might be a Chevy Coil​

Obviously looks like one or more folks who should have NOT been touching this got their hands on it. They did some minor rewiring to bypass these resistors.
Can I safely go with a compatible SIERRA Coil with an internal resistor and be done with it?
If so can anyone recommend which one. I really would hate to have to go and un-wire the wire job they did unless I have to..
Thanks in Advance...

All Products | iBoats

Since 1998, iboats is the most trusted water lifestyle online store for boat parts and accessories, boats for sale, and forums. Enjoy great priced products with fast shipping.

www.volvopentastore.com

Ayuh,...... Welcome Aboard,...... that's certainly odd, as the T-Bolt ignition is a Merc ignition, never used on Volvos,.....

1st question is,.... Which T-Bolt ignition,..??

 

[Scott Danforth]

1987 Volvos should have Prestolite distributors

Thunderbolt ignition comes on Mercruisers

So let's verify what you have and go from there

 

[Scott06]

If resistors were bypassed would think boat originally had points and was converted to electronic . As with other comments post a pic of what ignition system you have as it would be odd for someone to refit a Merc Tbolt to a volvo. Wondering if it is a Delco EST and OP is mixing up nomenclature?

 

[JohnnyA561]

Thanks for all the replies. Will be going down to boat and getting better pics.
- It's a Mercruiser ThunderBolt IV ignition system
- The Distributors are definitely Mercury Marine 90577
- Engines are Volvo BB260

 

[JohnnyA561]

Thanks for all the replies. Will be going down to boat and getting better pics.
- It's a Mercruiser ThunderBolt IV ignition system
- The Distributors are definitely Mercury Marine 90577
- Engines are Volvo BB260

Those are a mix of existing pics. Tomorrow hopefully I can get latest, in better light. I believe there were many more hands than I had anticipated on this project boat than I originally thought, Been a real Eye and Wallet opener for sure. The actual boat survey wasn't worth the $$ paid since they got the obvious but missed things like the ignition and steering issues that I feel they really should have caught.
I've replaced Motor Mounts, Risers, Manifolds, All Gauges, Gas tank sending units, Oil Lines, Fuel Pumps, Water Hoses, Steering Pump, Heat exchanges, New shaft couplings. Add the normal inboard shaft and rudder packing maintenance and just for fun I added dripless shaft seals. Also all brand new rule bilge pumps with high water alarms and overflow pump.
My last thing to do was put a new set of Carbs on since these are the original Rochester carbs, and are not taking mixture adjustments as well as they should, will probably switch them out to compatible Edelbrock Marines Carbs. I just was not counting on the Ignition system being what it is. Again, appreciate in advance any and all help and suggestions.

 

[Scott Danforth]

the thunderbolt ignition simply uses a standard (non resistor) coil available almost anywhere.

cant comprehend why someone would install the most expensive ignition system.

before you throw parts at it. go thru the thunderbolt troubleshooting guide in the stickies.

 

[JohnnyA561]

the thunderbolt ignition simply uses a standard (non resistor) coil available almost anywhere.

cant comprehend why someone would install the most expensive ignition system.

before you throw parts at it. go thru the thunderbolt troubleshooting guide in the stickies.

Thanks will do. Like I said, the boat runs ok, but parts look like they've seen better days, so better safe than sorry. I will be putting a meter on to see what I have first just to be sure with these existing coils.
As you can see from the below pics, on the Starboard engine (IMG_7974.jpg), they completely bypassed the resistor.
On the Port Engine (IMG_7979.jpg) they bypassed the resistor but used one of the pins on the resistor as a jump (that's a new one on me).
I've been around boats since around 14yrs old, seen my share of weird wiring before, but some of the things I've seen on this boat have defied logic. I've literally pulled out hundreds of feet of "dead wiring" that was just laying around, hooked up to panels or worse yet, directly to batteries and nothing on the end, just barely taped and laying there, amazing. I wanted a project boat, but his one is a little more than I bargained for.
All that type of nonsense I've cleaned up, all that external type stuff is now hooked up to a fuse box (All the Radios, GPS, Electric Reel sockets, etc), took a while, not as young as I used to be...
Again, Appreciate all the help and advice.... Safe Boating...