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Cybercop
06-20-2005, 02:03 PM
Can anyone help me with deciphering my engine/drive serial numbers for my 1991 Z33 Crossbow to help determine the correct model number to acquire the right service manaul.

I have followed the many threads regarding the HIN to understand that, but now that I am trying to get the right service manual to support work, I'm running into trouble. Full HIN is DMRZE252A191, which if I understand correctly breaks down to:
ZE - Indicates 33Z Crossbow
252 - Hull Number
A = January
1 = Production year 1991
91 = 1991 Model Year

While I have a 1990 RGD Service Manual that shows a distributor less (coil pack) ignition coil, I of course have the single coil with a distributor. Some reseach shows me that in 1991 there were RGD and RGF models, however since the HIN indicates January 1991 build, I am wondering whether the engines/drives really fall under 1991 or 1990 (which then brings PWC, PWR, PWS models into play) I found an article on sterndrive.info that indicates the serial number plate should indicate model number but where exactly would be the authoritative source of that, as the actual engine/drive serial numbers look nothing like that.

Of course compounding my problems was that the previous owner had to replace the original Gen IV starboard engine back in 2001 with a Gen VI base engine with intake, but retained everything else from the GenIV (e.g. ignition, exhaust manifolds, carb, etc...)

Any help....PLEASE!

Richard McCoy
06-20-2005, 02:53 PM
For Mercury engine parts go to Mercury Parts express on the web. Have your Ser.# for the motor and outdrive and zip #. This site will have a parts breakdown for almost all Mercury products.

Cybercop
06-20-2005, 04:57 PM
RGD ='s Cobra I believe???

Hi Scott, yes should have included that. There are 454HOs with Spitfire (EEMS) with KC drives. I am having a devil of a time trying to tune the engine that was replaced back in 2001 (REMAN I suspect) that just went through a complete top end rebuild (valve job included) and finding the right ignition/tuning info has been killing me. Even the flame arrestor cover with the Cobra touting Spitfire refers to the breaker dual coil model instead of the obvious distributor model w/single coil I have.

From what I've research the plug gap should be .045, however trying to fire her up on land has produced problems. She started up (after sitting since November and the top end rebuild) pretty good, however I can't get off idle without misfiring and/or rough.

Any clues/insights/ clairvoyance is greatly appreciated. It is killing me to be almost late June and not wet yet.

Brian Main
06-20-2005, 07:02 PM
Hi CyberCop,

I have attached pictures of the engine in my 1991 22 classic with the OMC 454HO. You can see in the first one that the model sticker is on the starboard valve cover. In the second one is a close up of my sticker. It shows model RGD and has the single coil setup you describe. The tune up specs are on the side of the flame arrestor cover. I'll see if I can get a picture of it.

Brian.

Brian Main
06-20-2005, 07:38 PM
Hi CyberCop,

I have attached pictures of the engine in my 1991 22 classic with the OMC 454HO. You can see in the first one that the model sticker is on the starboard valve cover. In the second one is a close up of my sticker. It shows model RGD and has the single coil setup you describe. The tune up specs are on the side of the flame arrestor cover. I'll see if I can get a picture of it.

Brian.

Here is the tuneup sticker on the flame arrestor cover.

One thought. If you have what is basically a Gen VI long block for one engine, wouldn't you need to use MR43LTS long reach plugs in that one? If you used the older short reach plugs, like for the Gen IV, in it the tip wouldn't even make to the combustion chamber.

Just a thought, maybe you already have that one covered.

Brian.

Cybercop
06-20-2005, 09:13 PM
Here is the tuneup sticker on the flame arrestor cover.

One thought. If you have what is basically a Gen VI long block for one engine, wouldn't you need to use MR43LTS long reach plugs in that one? If you used the older short reach plugs, like for the Gen IV, in it the tip wouldn't even make to the combustion chamber.

Just a thought, maybe you already have that one covered.

Brian.

Hi Brian,
Thanks for the pics, yes the clearly are the same engine and I have the same specs on the side of the flame arrestor cover, but they do not make sense....the RGD layout in the service manual appears to be for the older dual coil distributor-less system versusa distributor with the coil we both have?

The long reach plugs however are something I was not aware of/thought of (since the engine swap-out was pre-purchase before me). So of course I purchased same type of plugs that were existing in both engines (GenIV and GenVI) Champion RY15's.

I have swapped out the ignition coil from the Gen IV onto the VI just to rule that out, in addition to swapping carbs, same scenario.....fire up and idles fine, but coming off idle she spurts and sputters. Anything else you or anyone else might think of (such as the obvious that I am probably missing...:banghead:

onesubdrvr
06-20-2005, 09:18 PM
Hi Brian,
Thanks for the pics, yes the clearly are the same engine and I have the same specs on the side of the flame arrestor cover, but they do not make sense....the RGD layout in the service manual appears to be for the older dual coil distributor-less system versusa distributor with the coil we both have?

The long reach plugs however are something I was not aware of/thought of (since the engine swap-out was pre-purchase before me). So of course I purchased same type of plugs that were existing in both engines (GenIV and GenVI) Champion RY15's.

I have swapped out the ignition coil from the Gen IV onto the VI just to rule that out, in addition to swapping carbs, same scenario.....fire up and idles fine, but coming off idle she spurts and sputters. Anything else you or anyone else might think of (such as the obvious that I am probably missing...:banghead:
I would really look at the plugs, when I rebuilt my small block, that is the problem I was having, out of the water, engine ran fine, idled OK in the water, but once getting over 1000-1500 rpm, very bad sputter / back-fire. Plugs were too short (I went from standard to Vortec heads, but if there was a difference in the BB's, I'd check that), and also the firing order.

Wayne

Cybercop
06-20-2005, 10:31 PM
I would really look at the plugs, when I rebuilt my small block, that is the problem I was having, out of the water, engine ran fine, idled OK in the water, but once getting over 1000-1500 rpm, very bad sputter / back-fire. Plugs were too short (I went from standard to Vortec heads, but if there was a difference in the BB's, I'd check that), and also the firing order.

Wayne

Thanks Wayne. I believe the firing order for both the GenIV and GenVI are the same, but if anyone knows something different, please let me know.

The only other thing I have done to the GenVI that may/may not impact my problem is that I went to adjustable rocker arms (Crane energizers) and the 7/16 -3/8 studs to install them.

Brian Main
06-20-2005, 11:25 PM
I have seen several 454 HOs with the single coil system in the 1990 and 1991 period. But I have also seen one standard 454 with the distributor-less system. I always assumed that it had something to do the the HO engines that didn't get documented in the manual.

I am not familliar with the Champion numbers but the book I looked in shows the RV15 as an extended tip short reach plug for the older gen IV & V. If you can get a hold of a copy of "Big-Block Chevy Marine Performance" by Dennis Moore, it lists the differences between the engine generations.

One other thought just to make sure you have a gen VI block. Where does the Gen VI get it's fuel from? The Gen IV should have a mechanical fuel pump but 1991 was the last year that the mounting pad was cast into the block. Is the new engine using an electric pump? I only ask because I would want to make sure that you do have a newer engine if you put the extended reach plugs in it. If you didn't, there could be some nasty interference problems with the valves. :eek!:

Like Wayne verified, I'd change the plugs in the Gen VI first and see what it does. It might turn out to be an inexpensive fix.

Brian.

Cybercop
06-21-2005, 10:34 PM
Thanks Brian.

Yup, its GenVI with an electric fuel pump. Picked up the plugs this evening, however didn't want to piss off the neighborhood this evening, although it was tempting.... :rolleyes:

Will give it a go in the morning and let you know.

Brian Main
06-26-2005, 12:07 PM
CyberCop,

I am curious how you are coming with the sputtering problem. Did the new plugs make it any better?

Brian.

TulsaWolfe
07-09-2005, 07:35 PM
My Hull number is DMR167140677. I almost understand all of it. But I would like some one to explain it just in case I am wrong.

Also by looking at my hull number my Donzi was made Jun 1977, and I believe that makes it an 78 model. And I understand that it's a 16". Is the hull number 167? And would the 4 be the 4th of June or 14th made? Would like to try and get some help.

Thanks

ChromeGorilla
07-09-2005, 08:09 PM
Here you go. http://www.donzi.net/forums/showthread.php?t=35793&page=1&pp=15&highlight=hin

You have a 77 not 78.


DMR - Donzi Marine
16 - 16'
714 - Hull #
06 - June
77 - Model year

TulsaWolfe
07-09-2005, 08:27 PM
Thanks for the help, My title says that it's a 78 model. There is also a "C" after the whole thing. Does that mean anything special??