merc500 1973

[crem1]

Hi to clams_canino or anybody that is an expert<br /><br />Hope you can help me!!!(PLEASE)<br />I was on another "HELP" website but was shot down for being too amateurish in my questions, so you are my last hope to solve my problem. <br />Some background history: Last fall the engine started declining in power so this year I changed the Fuel pump and cleaned the Carbs. <br />I did a compressiopn check on my pistons and this is the result <br /><br />Piston 1 --- 110 PSI <br />Piston 2 --- 114 PSI <br />Piston 3 --- 129 PSI <br />Piston 4 --- 95 PSI <br />I did a spark check on the plugs and it passed at 20,000 volts<br /><br />Last I tried to time my engine and went through the first step which is alligning the flywheel with the distributor pulley. I started the engine and was revinng around 5100 RPM without the warm up lever. <br />Well I stopped the engine and went back to looking at the carburators and noticed that the throttle plates aren't synchronized. They don't open or close the same distances. <br />Is this a problem with the carburator linkages? I did not put the linkages together properly? <br />The throttle plates are supposed move together and the same distance. Yes!! <br /><br /><br />I saw your pictures on your boat and engine project and was totally blown by your expertise<br />Thanks in advance<br /><br />Alex

 

[timmathis]

Re: merc500 1973

Alex, Read this post,<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=29;t=014508 <br /><br />It may help u some?<br />Tim

 

[timmathis]

Re: merc500 1973

Was that compression test cold or hot?

 

[crem1]

Re: merc500 1973

Hi Tim!<br /><br />Thanks for the information I really appreciate it. <br />The engine was warmed prior to doing a compression test.<br /><br />Thanks again<br /><br />Alex

 

[crem1]

Re: merc500 1973

andy6374 in one of the replies said that he adjusted the carburator throttle plates. <br />Can you be more specific as to how you did that?<br /><br />Thanks<br /><br />Alex

 

[andy6374]

Re: merc500 1973

The three carb throttle plates are all in sync. by the throttle linkage. The linkage is connected to a spring on each carb by a cotter pin. On the far side of the spring there is a phillips screw. You can loosen the screw to adjust the throttle plates to the desired position and then retighten the screw. Also the throttle shutters should be fully closed when in neutral, if not the engine will idle very poorly<br /><br />-andy

 

[crem1]

Re: merc500 1973

Hi Andy!<br /><br />Thanks for replying but I only have two carbs and I'm not sure what part you are talking about. Would I have to take the carbs to reach the adjustment parts?<br /><br />Alex

 

[andy6374]

Re: merc500 1973

The throttle plates are in the throat of the carbs (2 in your case). They control the amount of air intake through the intake manifold and hence the fuel/air mixture. Take of the cowling and eveything necessary to be staring at the carbs. You should see the throttle plates move when you increase/decrease the throttle.<br /><br />Also, does anyone else think the 95psi on cylinder 4 is bad. This is more than a 20% decrease from cylinder 3.<br /><br />-andy

 

[joblo33]

Re: merc500 1973

I'd take off the little covers on the starboard side and take a look at the cylinders.<br />Eric

 

[Nos4r2]

Re: merc500 1973

^^^ yep-I'd try running it through with a can of seafoam or redex 1st though-with one cyl noticeably higher than the others it might just be carbon sticking up the rings.

 

[crem1]

Re: merc500 1973

Thanks for answering Guys!<br />I was going to ask what can I spray the cylinders with aside from Seafoam. I have a can of MERC engine cleaner called POWER TUNE. Should I spray liberally and then let it soak for a day?<br /><br />Thanks for all the input<br /><br />Alex

 

[crem1]

Re: merc500 1973

All the big fresh water fish live in Ontario and if you want to catch any of them and mount them on your trophy wall you have to come here.<br />But I digress, I want to find out If I can physically try to remove any of the carbon deposits that I will probably see when I access the port hole area or I'm going to damage something.<br />Thanks<br /><br />Alex

 

[timmathis]

Re: merc500 1973

Get a can of deep creep and try that along with some seafoam in the fuel. Deep creep is seafoam in a spray can. that may help #4. Good Luck ,Tim

 

[crem1]

Re: merc500 1973

Hi Guys!<br />Well I opened the port hole and sprayed the cylinders till I got some movement of the rings.<br />I then proceeded to adjust the TDC which was a big mistake. I could not start the engine.<br />Am I off by 180 degrees and have to readjust the TDC ?<br />How do you go about it the right way without any fancy dial gauges?<br />Thanks in advance<br /><br />Alex

 

[crem1]

Re: merc500 1973

Hi Again!<br /><br />To be off by 180 degrees the piston would be at the bottom of the cylinder?<br />Rotation of the pulley by 360 degrees would that have an effect?<br /><br />Thanks<br /><br />Alex

 

[crem1]

Re: merc500 1973

Hello to everybody!<br />I did a TDC, what I thought was a TDC, and then <br /> hooked up my timing device and of course took out the other three plugs and started the engine.<br />The light mark on the flywheel was highlighted but off the scale.(to the right as I'm looking downwards) I assumed the carbs and throttle were in the neutral phase.<br />Here is a stupid question, what do i do next in order to get to first base in the timing sweepstakes.<br />Thanks<br /><br />Alex

 

[timmathis]

Re: merc500 1973

Unless you pulled the timing belt how are you off 180? Pull #1 and get it at TDC Check timing marks at flywheel and distributor pulley do they line up?(Or close)

 

[crem1]

Re: merc500 1973

Hi Tim!<br /><br />Seems like I have two marks or lines on the flywheel. Pulling the belt would be taking it off the pulley to line up the lines. So do I try both of them as a reference point?<br />One of the lines does come close to the pulley line and that is the one that I used last.<br />Thanks Tim<br /><br />Alex

 

[crem1]

Re: merc500 1973

Hi to Everyone!<br /><br />Right now I can get the engine started with the warm up lever all the way up, even when the engine has been warmed up. At the moment if I lower the warm up lever the engine dies. <br />What can I do just to get the engine into gear?<br />Thanks in advance<br /><br />Alex

 

[crem1]

Re: merc500 1973

It's tough to get answers sometimes but I'll keep plugging.<br />"Loosen idle stop screw locknut and turn screw until throttle cam mark align with crankcase braket arrow.<br />Tighten locknut."<br />The above is an exerpt from one of your contributors. My problem is the location or lack of understanding of "throttle cam mark align with crankcase bracket arrow."<br />Thanks<br /><br />Alex