Bajapred

I have a 1988 265 Force that I repowered with an HP500 3 years ago..been running great! I have purchased a 250 supercharger setup & I am needing a bit of advice..1st, does MSD make a dist cap that will bolt onto my ThundV & is that a good idea?..my engine guy tells me to use the MSD box with the supercharger setup for better idle, I have also been told that the ThundV is just fine and not to worry about it, so does anyone have any opinion? I have done some research & I find people using both the red & the blue boxes...so I would lean toward the red just because of price and ease of RPM controlled rev limit. Are there any other issues I need to be aware of when installing this supercharger? I also will be removing the water circulating pump and T-stat housing in favor of a crossover setup. Thanks

baja

US1 Fountain

I used the ignition module from a V6 for the idle advance. Many have just kept the V8 with no issues at idle, so....

Don't know about your cap question.

I prefered the stock Merc ignition setup over MSD. Heard of many bad MSD boxes (my brother had 2 go bad in 1 yr), but no bad Merc stuff.

Mine had the anti siphon valve removed from the gas tank so not to choke down the gas supply. That's leads to expensive motor repairs. I think there are some larger aftermarket valves available just to keep it legal and safe. Make sure your fuel lines, fittings and fuel separator are upgraded in size. Don't upgrade your lines and separator, but keep your small fittings. It's all and everything. I 'think' the bottom half of my fuel pump was changed over from a high volume pump in order to get larger fittings on the pump. So double check on that part. My boat already had the blower installed when I got it, so not quite sure about the pump thing, other than many have used the stock pump with no problems.

Install a fuel press. gauge, and a bigger gas tank .

Good Luck

Bajapred

Well, I got a reply from MSD..they do not make a replacement for the Thund V cap...The people I am buying the Supercharger from have also suggested the V6 module. they say that the timing advance is better in it than the stock Merc V8 one. They have also said that my fuel pump will handle the supercharger no prob. But I have read that in some cases it needs to be changed..not sure why though. I am leaning toward keeping the Thund V and just replacing the cap and rotor, using the V6 module and an MSD blaster coil..and prob some new plug wires. My fuel pump is the one that is also an impeller water pump. US1, do you have a PSI boost guage to tell you what you are running on your blower? I plan on installing one of those as well...& can you hear your supercharger whine much?...I will also need to cut some extra fresh air louvers in the sides of my engine compartment to get more air to those twin 750's!...I am very excited about this upgrade, just hope my motor stays together...I am looking at mid to upper 600's in HP...

Young Performance

Baja
You can use an MSD box with the Merc ignition. Use the blue box (6M2). It is a sealed marine box. Also use the V6 module. It only has 14 degrees of advance and is all in much faster than the V8 one, which has 24 degrees of advance. US1 gave you some good advice on the fuel system. Update all of it to prevent any problems.
If your fuel pump drives off of the sea pump, you can change the lower pump section only. There is a higher volume pump assembly available. I think it runs around $150. The other option is to remove it and use an electric pump since that block does not have a provision for a mechanical pump. The pump you have was not designed to support that much power. Change it.
You should not only install a boost gauge, but also a fuel pressure gauge. Both are invaluable. Please feel free to give me a shout if you have any futher questions.
Eddie

US1 Fountain

yep, boost and fuel press. gauges at the dash. Also had a press gauge at the carb. I really didn't need the regulator as the mech. fuel pump couldn't deliver enough psi to unseat the needle. I added it more for looks. I was at 5# boost. Yes it whined. Music to my ears, loved it! Had a single 1050 dominator carb, but I think your twin 750 is a better setup with a more even fuel distrib.
1 other change was I removed the rev limiter box and harness. There is a harness that just plugs in place of it, but w/o the limiter. I hit 5800rpm all the time.
Sold that boat 4 yrs ago to another member on the board and the blower setup to another member. Now I is a twin all stock 502 guy. The blower motor was fun, but was a lot of work at times. If it's not dailed in right, it can be a PITA! Do whatever it takes to set up those carbs right from the get go, or you'll have a sour taste for blowers.

Blower setup, dash, returned to stock config when sold.

Bajapred

Ok, I will look into the pump upgrade..thanks for all the advice guys!..US1, looks like you had about the same amount of room that I have for the blower, tucks up inder that front very nicely. I am only going to run about 4.5psi of boost, so I hope to keep everything together. I wll give an update when I get it all installed and take it out for its maiden voyage!..be a few weeks though.. baja

cuda

There is a used V 6 module on ebay. It's bid up to $5 right now.

http://cgi.ebay.com/ebaymotors/ws/eB...7428&rd=1&rd=1

US1 Fountain

Actually it was more than a little tight. A little 3/4" clearancing was done by orignal/previous owner.

Panther

Don't set base timing at idle, rev the motor and set it for total advance. The V-6 module will give you more timing at idle which will help your idle quality with the blower.

You could also scrap all that stuff and get the Crane ign. box, which already has different advance settings you can play with. You can utilize the stock distribuitor but you will need to index the rotor.

You may be able to get away with the stock fuel/water separator by drilling/tapping the housing for bigger fittings. Put bigger fuel lines from the tank to the motor, you may even want to modify the fuel tank pick-up. Teague makes a nice fuel/water separator with 1/2" fittings. Go with the bigger fuel pump and overbuild the fuel system.

I have bigger motors but I run 1/2" fuel lines with a 130 GPH mechanical fuel pumps and secondary 140 GPH elec. fuel pumps.

BadDog

BP, I have a Force 235 (identical from windshield back) with a B&M 250. Hope you are handy with a Dremel tool! I had to do a little cutting here and there to fit it in. Not a problem though. The lip on the rear bench needs relieved 1/2 inch for the width of the blower. Cut a relief into the seat back and minor upholstery work to center section of rear bench seat.

Very easy to do. I can send you some pic's if you want to see what you are getting into ahead of time. I also have some tips for quick removal of the back bench and supporting mounts. I can have may back seat slid forward 24" in about 5 minutes. Prior to adjusting the stock mounting points and upholstery mounts it was a two hour ordeal to just get at the seawater pump.

The stock underhatch storage sheets will need modified and locked down to clear the flame arrestor. Picture would be worth a Kiloword.

I second the Crane box option. I relocated the stock system and it is ready to go as a backup.