jasonmd2

iTrader: (4)

So I have a new to me "hole in the water that I dump $$$ into" and have a few questions about the 525Sc's that are in it. These are the 525SC's with the baby Weiand 177 blowers on them. It's a 1995 Cig Top Gun

1) What is the difference between the blue and the black engines? In my search I have mostly seen the blues ones, but mine are all black

2) What can anybody tell me about the loading up issue with these engines? I have heard that this is a problem with them. If you don't idle @ a dead idle then the plugs will load up because it comes off the idle circuit. Is this true? If so, any way to improve on this? I boat in So FLA area and there are 1 million no wake/minimum wake zones so if this is the case it seems like I will be changing plugs when I change oil and I am not looking forward to that challenge every 25 hours...

3) The plugs that I pulled out of it last night were AC R43T equivelents, which through searching seems to be two heat ranges hotter than what Mercury recommends...think this was an attempt to try and counter the loading up? I put NGK UR5's in there with the extended tip, should be okay right? I read that others used them with good succes.

4) Anybody try a smaller carb on these engines? Could this Dominator 1050 be a little over kill?

Thanks in advance guys!

paulb32

I have pair of 525sc's in a 98 I bought this spring. They idle seemingly forever as long as warm, a bit rich when cold. Idle in gear though is a bit high at like 850 ish. Or up at 1100 for a while too. And there are AC Mr41t's in it. Tuning is everything but tuning reliable idle with 4 corners takes some time.

jasonmd2

iTrader: (4)

Yeah I think at a minimum I need to rebuild the carbs...the idle seems a little off. I just got the boat so am still playing around with it, learning it and working out the "bugs". Thanks for the input Paul.

Anyone else care to add anything

glassdave

iTrader: (1)

I have a pair in a 38ZX Donzi that have ran pretty much flawlessly for 270 hours. Never had any loading problem although one seems to be a bit cold blooded for a few minutes til its got some heat in it but then its fine. I have only seen ones that are black with blue components (valve covers, carbs , intakes etc.) Are yours all black?

jasonmd2

iTrader: (4)

Hey glassdave I read a bunch of your threads on these motors...thanks for chiming in.

Yeah mine are all black...everything, alternators, blowers, valve covers are actually polished thou, but pulleys are blue I know both motors were "freshened" up already, but I know bottom ends weren't done so I doubt they painted the motors black...weird huh? Here's a pic



As far as the loading up goes you never had any problems? Do you have a lot of areas that are no wake/minimum wake? That seems to be the problem, apparently it's either dead idle or under acceleration to use the additional fuel the Dominator's pump in. Still seems strange to me that you apparently can't cruise at a slightly high idle for the minimum wake zones...need to do some more research

Bodi

You are running spark plugs that are 2 heat ranges hotter and at sea level. I would make a cruising run and pull one of the back plugs just to check your jetting. Then make a full throttle run and do the same. The cooler plugs tend to make the boat run richer with the same jetting but prevent hot spots and detonation. I would also keep your boost around 5psi if you spin the 177 up faster to say 7psi you are just pre heating the intake charge and with those warmer plugs I would'nt recommend it. There are a lot of people on here more familiar with blower motors than I am and I boat at 6K feet but I have been told to be conservative with blower set ups.

glassdave

iTrader: (1)

Yea that is odd. Are they they original motors for your boat and did the previous owner give you any history on them? Those do not appear to be factory 525SC's, theres a lot of non OEM parts i see in the pics. From Merc they either had CMI's or Gil's and those are not the right valve covers of course all that could have been switched at the time of overhaul. The factory set up also uses a water pump rather then a crossover, interesting. Those may have been shop assembled 525's its not uncommon to find these blowers for sale from time to time.


I have not had one issue with these other then the slightly cold blooded port motor but that clears up after just a few minutes. I have a few mile idle down our river to open water and its never loaded up at all. By the time i hit the marker buoy she's properly warmed and gets right with the program. Ive never touched the carbs and it has the original plugs. Runs like a top.

jasonmd2

iTrader: (4)

Hmm, as far as I know they're original. I know the whole history on the boat, I'm the third owner. Boat was sold through Cig/Lip-Ship and I talked to Phil. Seems those motors were stock from Cig. I do know first owner had port motor rebuilt and I'm thinking maybe put the polished valve covers on it. Guess I need to do some more diggin on the full history.

Anyways, I was cruising slightly above idle and I think that's what fouled the plugs. I replaced the Champion RV8C (AC R43t equivalents) with NGK UR5's which are supposed to be equivalent to AC R41t which is supposed to be stock. I'll hopefully run her this weekend and see how she does...

As I said thou, I think I will need to rebuild the carbs...there was always a problem with a rough idle so I think maybe the jetting is off or something...also wondering if I need to adjust since the boat spent the last 5 years in CA.

paulb32

I'm with glassdave. For me it's my starboard motor needs a bit longer than port but just diff tune. When warm, a flick of the key starts em both any time of the day after sitting any amount of time. My 98's have CMI Etopps and the blue covers & such. I see the same differences and agree they appear to be shop built duplicates-a very common practice. On mine the carbs, lines everything is blue. When the carbs are cleaned they end up removing the blue at times.
I suppose you could tell by the s/n IF you can see the tag at the left rear of the motor. 525sc's had their own series I believe.

Back4More

Stock carbs were 1050's on the 525's