Supercharged starting hard
 

Hi my friends. I have a Baja 1997 727 2 with a 454 supercharged weiand with single 4 barrel carb. The engine was rebuilt 20 hours ago by a very reputable mechanic .I know very little about the supercharger. I pump it about eight times to start. When it starts I have to play with it to keep it running until about 150° temperature. I feel the idle may be a little low at 500 RPM. Runs fine afterwards but when coming to the dock at idle it dies. I live in Clearwater Florida and would like to find a reputable mechanic that knows about these engines and superchargers. Anyone have any ideas of what could possibly be wrong which is a loaded question I know. Does anyone have someone in this area of St. Petersburg that knows about these engines which superchargers. Thank you for putting up with my ignorance.Boat just came from Idaho

it sounds like you have a tune up/timing or carburetor issue, either is easy to fix. I unfortunately don't know of any mechanics down there.

Is it a mercury 525 Sc with the 1050 Dom or is everything aftermarket install. If so what carb is on it. Could be a simple air screw adjustment down to a carb rebuild. I’d definitely bump the idle for starters along with checking/adjusting your 4 corner air screws.

Something you can easily do yourself. Keep track of each idle circuit screw by turning them all in one at a time and then turn back out 1 1/2 turns. Just write down what you do but sounds like your starving for fuel when cold.

You can fine tune one at time for best idle. Possible vacuum leak otherwise. Just a guess but I’d start with the basics. Hope that helps before you have to take boat to a mechanic.

Just another easy self check is your float bowl levels in addition to the above. Best to do while running however with your issues might be difficult so just check after running and engine cooled down just remove the front and rear screws and rock the boat a little and if you see a little fuel seep out then that's likely not your problem. Not sure if you have the plastic see though sight plugs or not. If so you should be able to see fuel without removal.

Thanks guys so much for your advice. Seems like I have a starting place. Because it’s a supercharged engine I figured it was going to be more difficult than that but we will see I hope

What do you think the Idol should be around? Right now it’s around five to almost 6

750-800rpm

500 rpm is way to low of an idle. And you shouldnt be having to pump a punch of times.... I do about a half a pump, open the throttle to just above idle, turn the key and its lit. 177 blower, dominator and timing locked out at 32 degrees.... Let it run for a minute or two at 1100 then it purrs at 750 with no problem going in and out of gear.

Thank you my friends for much help. Have a mechanic that’s going to look at it tomorrow and he knows a lot about them so we’ll see. Again thank you

At 500rpms, I'm not surprised it stalls. Bump the idle up to 750-800rpms in neutral

Will do

Curious what ignition he has and if its locked or not. If not locked out what the initial is set at.

If you have a guy with basic knowledge do a quick once over I'm certain your issues will be solved or even yourself with advice given.

Cap has corrosion,plugs slight rust,idle of course is low,ya think!gonna have carb rebuilt due to bad gas prior to getting boat,Be safe and stay well Change fuel filter already. Do you think that’s enough reasons? I do but will find out. I will get back to you with the results. Thanks to everybody for all their concern and help.Be safe and stay well

Initial timings everything on a blower motor. I dont like to see locked timing on anything other than all out race stuff since most motors on my dyno arent as happy in the 3800 to 4800 range pumped full of timing BUT we often make and install a w a more aggressive timing limiter bushing for MSD distributors allowing us to set base timing at 20/22 and still have 32 or 34 total and it tremendously helps weak idles.

If the boat just came from Idaho, it's probably setup (tuned) to run at altitude. ;)

sounds lean at idle, or air bleeds clogged with crud. I would blow the idle circuit out with carb clean, reset idle mixture screws and idle speed setting. Id ditch the locked timing as well

OK my friends. I had a mechanic check the boat motor. He said it needs a cap, Rotor , Spark plugs, a carburetor rebuild kit due to old gas that has been sitting in the gas tank for two years which is now completely cleaned with a new fuel filter and new 90oct no ethanol fuel. New ignition module sensor, Timing is a little off, And a test run. His price was $1150. What do you guys think.? As far as price. Old fuel was starting to varnish. I think this price is way out of range but I don’t know so I’m asking.

None of that stuff is hard to do yourself. So, either learn to do it yourself, or write the check. Curious though, why are you running 90 octane fuel with a supercharged engine? What is the compression ratio, and how much boost do you run?

Actually, I do know how to Tune an engine,however I am now 73 years old, I never rebuilt the carburetor and the 90 octane is the only fuel available with no ethanol. I do not know the compression ratio and since I have only run the boat once I did not notice the boost however the mechanic that built the motor said that the boost was right on. So what do you think of the $1150 cost?

Price seems high, but I really dont know because I never paid marine mechanics, always did my own stuff.

I personally wouldnt run 90 octane, unless it was very low compression, and low boost. I see alot of guys that believe if the fuel is non-ethanol, they can get away with lower octane, but that is false. Octane is octane.

A long time ago, I was at the marina where i stored my boat. A marine mechanic was there , working on another boat. He came by as I was setting the timing on my engine with a timing light. He proceeded to tell me how he doesnt need a timing light, or use one anymore. He is so good, he just times them by "ear". Point being, there are good mechanics out there, and there are terrible mechanics out there who are parts changers at best. Once you find a good one, hang on to him. He might cost more up front, but it will save you in the long run. A parts changer will have you writing checks instead of boating.

If he`s good, reputable and gets it running correctly
$1100 seems like a good deal.

I would pick octane requirement over ethanol free 90. From 1999 - 2017 my Mercury 280's and then 300xs had no issues on current ethanol fuels. Since then my boat only needs 87. That's my opinion! BTW... there are some land gas stations selling 90 ethanol free octane for $4.60 last season.

Without an invoice/estimate with a cost break down of exactly what he is doing, it is hard to tell.

https://www.mercuryracing.com/produc...erndrives-faq/

https://www.offshoreonly.com/forums/...erc-525sc.html

No vacuum/boost gauge?

I remember back in 92 was crucial to run no less than 90/91 octane per merc. I believe it was because it was early on and they loosened up a bit with 525 SC. And yes they did run pig rich set up from the factory.

The 525SC was 92 Octane required by Merc. Lots of people did post that they had run 91 regularly though and a few said they ran 89 in a pinch.
The 575SCi was 91 Octane required by Merc.

The reason for 90 oct s Ass nd non ethanol is that my tank is aluminum . Do not want corrosion

If you do have a mechanic do your work be sure tell him you would like to have the parts that were replaced. Sounds like your basic maintenance. Did he do a leak down? Would suck if you got it back with same issues. Might be time to replace items mentioned regardless but I'd like to get a grip on what exactly is the problem. You can check the plug wires with an ohm meter. Can easily remove cap and clean it up and check for a crack. I just hate when a mechanic will say it needs all this and that and after all said and done your still back to square one. You can inspect plug wire easily look for any arcing. Nice to do at night as you can see arcing very quickly. My best guess would be timing or carburetor,. It least your moving forward anyway. To bad you don't have a twin brother to this one and starting parts one at time.

I run e85 in my street car. Car will sit for months at a time. Never had an issues with corrosion. My last injector rails were bare aluminum. No corrosion in 5 years when I had them.

Just an opinion from a guy using e85 for about 10 years.

I just opened my fuel tanks..after sitting with fuel from 1994.

Varnish...but still smells like reasonable gas...I was totally shocked...I was expecting skunky old gas smell.
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Aluminum tanks were 100% perfect. Try that 10 10% ethanol now...!!!
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It is possible to anodize the inside of the tank to run ethanol fuels...just gotta find the right shop to do it.