454 Troubles Continue

kwinters · Post by **kwinters** » Sun Nov 22, 2009 4:33 pm

OK. I back on this issue with all new fuel tank and any part that goes with it. I have 17 psi vacuum at 900 rpm. Slight flutter maybe half a psi at that point. Raise engine rpm up to 1300 rpm no load and it will kick up to 1600 without advancing the throttle. You have to back down on throttle to get it back to 1300 or so and as you ease up from there it will advvance on its own 300 or 400 rpm. The slight rough idle goes away as well as soon as the rpm advances up. Under load both engines seem to have the same power up to 2800 prm. You can then gag the one engine and she will go right up to 34 or 3500. You can do the same to the problem engine and she will struggle to get up there. There is a large power difference in the two. Tank,new. Filters,new. Fuel pump, new. Carb, new. Coil, new. Relay, new. Distributor, new. Wires,new. I am having issues with setting the timing as the information from marine power is skethcy or at least mot clear. Initial timing set at 12. total timing 30 at 4000. Wish I could get there again. Anyone can offer any suggestions would be helpful. I read a old post on marine power issues that a guy fought this problem for 6 years.

dealerschoice · Post by **dealerschoice** » Sun Nov 22, 2009 7:01 pm

I'm sure you changed the plugs also. What year is your set up? Try changing anything you can switch from one engine to the other. I am not sure what is left to switch, maybe an electronic module. Have you checked compression? Give us any info you can. Good luck. Scott 1987 B33 SF Dealer's Choice V Edisto Beach, SC

dealerschoice · Post by **dealerschoice** » Sun Nov 22, 2009 7:08 pm

Sorry about the questions. Just saw the other thread. Scott 1987 B33 SF Dealer's Choice V Edisto Beach, SC

lobsta1 · Post by **lobsta1** » Sun Nov 22, 2009 8:05 pm

Kevin, Ken, Kenny, Karol, Konrad, Kelly or whatever name you go by; try swapping the timing module between both motors. In 1992 I repowered my old Sea Ray with a Marine Power 454. In 1992 it was running great but before I sold it to a friend , I went through everything with a fine tooth comb. At that time I also put in a new timing module. He picked up the boat & the next day called me & said boat ran like crap. I told him to put the original module, cap & wires back on. He didn't & I had to go down & troubleshoot. First I found a pinhole leak in the line between the fuel filter & the electric pump. Sucking air in with the gas probably did not help the WOT. Then I swapped back in the original 10 year old timing module & WOT was back up to 4400. Put the "new" one back in & struggled to get over 3200. The mechanic who did the repower also told me the modules were prone to corroding through on the bottom & then acting wacky. Of course none of this may apply as we don't know what vintage the engines are. Al P.S. you have no info in your signature or profile, so I assume this is on a Bertram.

kwinters · Post by **kwinters** » Mon Nov 23, 2009 5:50 am

A compression check was done. A issue I am having is that the two timing gauges are different on both my engines. I can not tell for sure where zero is on the problem engine but have concluded where I believe it is. Al, I got out my old distributor last night to look at the part number on the old timing module and it is not close to either of the two I have put in since. The origonal was corroded ny that is one factor that has been changes thru the entire aggravation of this engine. Also, the timing is moving around while running, not a small amount but like it is firing at different trigger points. It stays in place for a few seconds and then jumps to a new spot for a short time. This movement is almost consistant to the spot it moves to. Today. pull and replace plugs, find exact tdc. If plugs are good (have about 20 hours on them) I am going to change out the module to the factory one and see what happens. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

kwinters · Post by **kwinters** » Mon Nov 23, 2009 6:27 am

The engines are 1996 commissioned in 1997. Less than 1000 hours. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

Post by **dougl33** » Mon Nov 23, 2009 7:43 am

Have you tried swapping parts from engine to engine? Back in 2001, I had less than 20 hours on a brand new electronic ignition on my 1981 28 Bert. After swapping several things back and forth, it wound up being a $70 pickup module on the distributor. It was brand new (less than 5 weeks from Mercruiser) and it failed. Mercruiser, of course, would not warranty the part.

lobsta1 · Post by **lobsta1** » Mon Nov 23, 2009 11:15 am

Kurt, You are probably b*lls deep in it now, so let us know how you make out. My bet is the timing mod. For curiosity sake, is it the reverse rotation engine? Good luck. Al

kwinters · Post by **kwinters** » Mon Nov 23, 2009 1:51 pm

Al: I took the old timing mod out of the old dist. The part numbers for the 2 old mods ared not even close to the new one I had gotten from Jerrys marine. Yes, it is the counter rotaion engine. The engine rpm advancing on it own went away. The rough idle is still there but now we have the new carb adjusted to the old mod and the timing is all off. I also imagine that the plugs are fouled as I did not get to that today. Will start to get everything set right in the am. Do another compression check and view and replace the plugs. Thanks for the help. I will report in on the next phase. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

kwinters · Post by **kwinters** » Tue Nov 24, 2009 8:53 am

OK. Here is the latest. I checked my vacuum gauge to be sure the line from the engine to the flybridge was good. Holds pressure fine. Started up to set the timing by vacuum until I can get the tdc located. Vacuum came up as I set the dist. by eear to highest idle and backed off just a little. I I began to hear what sounds like a vacuum leak. As I rebuilt the other carb last year and the carb shop left out one of the plugs for the power boost I seemed to remember the same type of sound. Removed the flame arrestor and closed the choke buterfly within a 1/8" slot along the leading edge of the butterfly. RPM jumped thru the roof and the engine smoothed out to almost normal. Let it go and it drops off and runs rough and idle drops off. I am trying to decide which way to look. I will look for a leak visible since I think I can hear a leak but see nothing to cause it. From there, if I have a valve issue would it have to be only a exhaust valve not closing to cause the above or could it be either. Back for the compression check. This thing is killing me. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

franklyprice · Post by **franklyprice** » Tue Nov 24, 2009 2:55 pm

Kurt, A leaky valve will most likely cause no appreciable problem at higher RPMs. Of course if you have zero compression because there simply is no valve left, then you have a problem but just a reading of say 50 PSI will make no difference as soon as the idle comes up. It sounds like the vacuum leak or carb troubles are most likely the culprit. Also , the timing is super important. It's easy to make the engine run nice by ear without a load on it but that will most likely be too much advance and it will detonate without you hearing it and cause real damage. You must get that timing mark figured out and start at 10 or 12 degrees initial. Sounds like you're almost there.

Donmystic1 · Post by **Donmystic1** » Tue Nov 24, 2009 3:21 pm

Take a can of carb cleaner and with the engine running at idle spray around the outside of the carb to locate any vacuum leaks in the carb, intake bolts and manifold bolts. If there are leaks the engine will speed up as it sucks in the cleaner. Keep a fire extinquisher handy.

kwinters · Post by **kwinters** » Tue Nov 24, 2009 7:29 pm

Thanks guys. We will be back on it in the morning and I think we can track it down now that we have a direction on the vacuum. Question on the carb cleaner, when you spray it into the carb it normally wants to choke it out. When you suck it into a leak the idle will go up as it is such a small amount? I will write a tip issue ont ths episode when we get done. Step by step to chase this down. Next report to follow. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

kwinters · Post by **kwinters** » Wed Nov 25, 2009 1:50 pm

TDC located. Timing has been set perfect with ititial timing plug. New Plugs today. One was fouled, # 7 or something. The rest were clean. Compression check on all cylinders. 140 on all but 2, 135 on those. Adjusted the new car air mixture screws until engine was as smooth as possible. Vacuum now at 15.5 to 16.at 900 rpm. By moving choke butterflys the engine increases and runs great. Vacuum goes up to about 19 and idle incresaed to 19.5. Checked to find leaks with starter fluid. Have one possible area that increases the rpm from 900 to 1080. It is close to the carb. so I am not sure it is not the fumes of the starter fluid goin into the carb. One Large Question. Looking thru my pile of used parts I have 3 different carb base gaskets. One has only the holes for the butterfly cutouts. One has the inside section cut out but still has a small section in the front that covers the area inside where the idle mixture screws are located. The third is open all inside the carb. To me, it looks that the macining allows air to flow from the center to the left venture and you would have to cover that from area to make it work properly. Anyone know why the made 3 different gaskets would help. I am going to change the base gasket the the 4 hole in the morning. If that is not the issue, start stripping it down and see if the intake gaskets are gone, magniflux the intake if we don't see anything. Might as well pull the heads and finish it at that point. Happy Holidays. Kurt Winters "CREWS INN" 1977 33 Bertram FBC North Palm Beach, Fl.

Miss B · Post by **Miss B** » Thu Nov 26, 2009 9:47 am

Happy Thanksgiving. The different carb gaskets were used depending on the manifolds. Flat carb mount got one style, angled carb mount got another. Some were with open spread bore, some were partitioned off between the primary (small) and the secondary (larger) carb barrels. The fact your RPM's jump when you close the carb choke indicates a vacuum related problem to me. When you choke off the carb RPM's jump because you are correcting a lean burn condition. Make sure your carb is evenly torqued down on the manifold. Then check any rubber plugs on the carb to make sure none have small cracks that cause vacuum leaks. Check the carb casting plugs to make sure none are allowing a vacuum leak. Next, put a timing light on your # 1 cylinder. Watch the timing mark to see if it jumps around when you crack the the throttle. It should advance quickly and then stay relatively stable. If it does not you should check your distributor bushings to make sure there is no play in the bushings. Next, if you hear noises from the front of the engine, you may have timing chain slap. When you initially rev the engine the timing chain becomes taut and when the RPM's settle in the chain slap returns, allowing the timing to jump around. It will also cause fluttering of your vacuum readings, just like a leaky hydraulic valve or bad lifter. Initial timing on a 454 block set mechanically should start at about 4 degrees before top dead center. Someone else suggested a timing module check, and that could be an issue a well. Before I pull the distributor to check it I would check the timing module, it is alot easier to check. Engine vacuum is the "blood pressure" of an engine. You can diagnose many ailments by that. Finally, when two adjacent cylinders have the exact same compression reading you may have a leak in the head gasket between those two cylinders, but your 135 lbs are relatively healthy. Make sure your manifold riser gaskets in that section are not leaking either. That could allow one cylinder to suck water in when the intake valve is open. Finding these leaks is a step by step problem, but unlike computer controlled problems, they can be found and solved. Let us know the outcome. Regards, Miss B