Threw a blower belt
 

Idled out of the channel, got on plane and ran about 2-miles at 3000 rpm. pushed the throttles and starboard motor would not rev higher. stopped to check the engines and found the idler pulley bearing on the blower had desintigrated and thrown the belt. Never saw temps go up or any other signs. Replaced the bearing and seems to run fine.

Should I be concerned or check anything else?? How long can you run the motors at low rpm w/o a blower belt? Idled a couple minutes and ran below 3000 for a few more. :(

Thanks

I beleive you can run it for as long as you want with out the blower belt, but it only has about 1/3 the HP, ran one for several hours before just to get home, put new belt on and everything was fine.

Thanks. paranoid I guess. we idled in on one engine.

You generally don't have to worry much when you break a blower belt, just get her back on plane and run home real easy.

If you run your oil pump off your bottom pulley be sure you didn't damage your oil pump belt our pulley..

last Fall while running real hard our broken blower belt took out the oil pump belt,thus zero oil pressure and a snapped rod the following day..
We have since fabricated oil pump belt guards for this season.
Hope this helps!

Are you running 575sci power? I just seized a 256 blower (with 200 hrs on it) this past weekend. Popped the belt off and couldnt even get it on plane. Anyway, just a matter of time befor these tiny blower experience problem.

Ya need a bigger blower? I know someone that knows someone :D

This really depends on what really happen and what SC you have. With a roots locked up, rotor to case or rotor to rotor, you going to have almost no power because the engine can't get air through the SC. If it had a bypass system, well then it would at least feed through that. If the belt just falls off, then it should still make somewhat decent power, although nothing compared to before because the sc will still spin when the vacuum from the engine sucks the air through it.

Thanks

Dustin, I would love to whipple it...and it might just pay off in the long run...however gas is going to kill me this year. My insurance company also decided they did not want to cover cats anymore so my rates are doubling also.

I really lucked out on my blower situation on the 4th. After the blower seized, I idled back to the sandbar, (still in pretty good spirits from running sub hundred speeds with heavy load) wrote the day off and cracked a beer. As luck would have it a guy walked bye, started talking about my situation and he had a brand spankin new blue merc 256w sitting on the shelf in his garage. $1100 bucks later and 2hrs I was back in business.

Dustin, I also went down to a 3.5" pulley and a 126* thermistat. Am I pushing the limits of the fuel map? It was my understanding that higher manifold pressure would throw more fuel at it. I did a shut down plug check at 4000rpm and they looked on the lean side.

Wow, right place at the right time. Good to hear. The stock map does not add more fuel as the boost goes up, its the same as stock boost fuel so it does lean up when you change the pulley size. It's a good idea to have the ECM modified for just a touch more fuel at the higher boost. For whatever reason, mercury did not even extrapolate the map. No problem other than that. Normally, I touch the boost fuel table a touch and bump the rpm limit to 5600rpm.

Thanks,
Dustin

Thanks all for the replies. the blower was not locked up. Ran fine to 3000. I can get the boat on plane w/out going over that. Once I replaced the idler bearing all was good.

BTW they are 575sci with Whipple intercoolers. Ran 92.6 at 5300 the other day. Still have 300 rpm left.:ernaehrung004:

Motor ran great with the new thermistat and pulley. One thing has me worried...cruising @ 3800rpm, rpm momentarily dropped 500 rpm for a second then came back. This happened twice on the last run of the weekend. It also happend after I switched totally to my port tank (which had contained 2/3rds last years gas). Was the ECM pulling timing because of detonation? Water was @ approx 60* and my water temp hovered around 130*. I need to get an AF meter on this and do it right.

I doubt it was timing being retarded. The knock system is not even close to being sensitive, and at part throttle, you were probably no where near a knock window. If it dropped that much, I would check/change fuel filter and also inspect distributor/cap/rotor/wires. If you have 204 hrs on those, they need to all be replaced. By the way, don't bother using any part of stock distributor, just throw it away and install a new Mercury Marine or GM marine unit, all others cause multiple issues.

Thanks,
Dustin

You blower guys...help a virgin blower guy out here. Did I do right or what?I have a 250 Blower shop unit with a dominator on top. The fuel pump is an Aeromotive A1000 with an Aeromotive bypass regulator that allows a 1 to 1 increase. If I understand it correctly...1 pound of boost increases the fuel pressure 1 pound, with the idle pressure set at 7 PSI. I set the timing at 28* total on a MSD distributor. All the fuel lines are stainless steel JIC fittings at -8 (1/2).

I really dont need a blower...just wanted one. Love to here that blower whine when cruising.

Thanks for any and all info and or suggestions.

Sounds like you did a good job. Just watch your fuel psi, make sure you don't exeed 10-11psi, you just need enough to keep the bowls full.

Dustin??
 

Hey Dustin,

I have destroyed (2) both Idler pulley bearings since I added your intercoolers (within 10 hours run time since install). If you remember the belts in the kit were too short (could not get them on). The replacement belts you sent me put the idler bracket about halfway through it's stroke. The blowers were just gone through at 100 hours but Idler bearings were not replaced. Any thoughts? Just coincedence?

Thanks

Thank you for your info. I want to learn the "how-to's" but I dont want to break anything. I will watch the fuel pressure, but I might have to bump it down on the idle a hair to stay under the 11 pound max. Again...thanks :ernaehrung004:

That or just run the regulator without the boost reference if it becomes a problem.

It's possible that its a coincedence. The belt length shouldn't effect pulley life. Bearings should make far past 100 hours, keep an eye on them, after a few hours, take belt off and feel them by hand. 1/2 way for idler bracket is perfect.

Is that a special bearing? Anyone know a replacement P/N?
Found a SKF Double Row Ball Bearing with same dimensions.
P/N 5203A-2RS1TN9, rated to 10,000 rpm. Will this work?

$39 at local bearing distributer. Merc (BAM) wants almost $280 for pulley and bearing......

That will work, SKF makes a nice bearing, as does NSK.