Thunder Bolt IV Upgrade?

[klawton55]

Hi, I have a 24' 89 Sea Ray with a 7.5L Mercruiser. The engine runs good, but I would like to make sure that I am getting all my bang for buck out of fuel. So my question is do I stick with the thunderbolt IV ignition or is there an upgrade that you would recommend. And if the thunderbolt is a good option should I look at a better coil than a general grade coil?

 

[Don S]

Re: Thunder Bolt IV Upgrade?

Assuming you meant a 7.4, and not a 7.5.
Keep it tuned up regularly, do a compression check, confirm timing and advance timing, keep the carb and choke adjusted properly and you are doing the best you can.
You might spend a few hundred bucks on a newer ignition system, but the chances of the gain in fuel mileage ever exceeding the cost of the upgrade is highly doubtful. (even if the upgrade cost only 50 bux)

 

[klawton55]

Re: Thunder Bolt IV Upgrade?

Thanks Don, I did mean a 7.4L. I appreciate the info. I am glad I asked before I bought anything!

 

[achris]

Re: Thunder Bolt IV Upgrade?

Aside from going to MPI, the system you have is about as good as it gets. Just do the things Don said and you can't go wrong.

Chris.....

 

[Bondo]

Re: Thunder Bolt IV Upgrade?

Ayuh,.... I agree with Don, 'n Chris,... The T-Bolt IV is 'bout the Best marine ignition there is...

 

[Speakrdude]

Re: Thunder Bolt IV Upgrade?

I onstalled a TB IV on a Volvo 5.7l, in an 84 model BAyliner 2750, a while back. (removed the mallory marine system) Ran great from then on.