New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

[Stan's Customs]

Hello everybody..<br /><br />1984 5.0 Mercruiser Four Winns<br /><br />I just got some "like new" take off manifolds and risers on E-bay. Looks like these have a "big" hose exiting the riser...actually the smaller exit is there just doesn't have the hose clamped there, but on the larger part .<br /><br />My old risers have a 3" hose exiting...that bells out to a 4" I'd guess. <br /><br />Can these newer risers be used on the '84? If so where can I get the large riser hose..assuming that one "large" hose connects the riser to the exhaust....instead of a reducer type hose to connect them.<br /><br />The new risers don't have a small hose fitting on the front of the riser going to the thermastat housing like the old one either.. I am supposed to install that.....correct? And is the manifold to riser gasket different too??<br /><br />Thanks ...Stan

 

[MGallik]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

I'm looking for info on risers too Stan. <br /><br />About the book, sorry. They said they didn't carry it. Even after I stated I'd just bought a copy 3 days ago at that very store, the lady said I couldn't have as it's out of print... Geez...

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

That's OK 1900sx...<br /><br /> It was worth a shot...Thanks for the effort...I really appreciate it..<br /><br />Maybe next time..<br /><br />Stan

 

[Laddies]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Risers for center riser manifold are mostly interchangable as are the log type manifold risers but atre not interchangable from one type to the other ck in a Sierra, NAPA parts book for Gaskets, hoses etc

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Thanks Laddiesservice..<br /><br />They will bolt to the manifold, that much I know. I'm wondering how to connect the late model risers to the old style exhaust pipe. I don't find a Mercruiser part number for the hose, plus I'm not sure which temperature rated hose to get in the cut to fit.( provided that is the right way to approach the hook up.) The stock set up has a 4" exhaust pipe and a 3" riser exit. The new risers I have are 4" with a 3" pipe with a rectangular trough on top protruding from the 4" part..? Odd lookin'..<br /><br />Also I don't know if the riser gaskets are different...some risers have a hose going to the thermostat housing and some do not...what's up with that?<br /><br />thanks

 

[Don S]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Since you are doing some backyard engineering here, don't expect to find Merc parts to pull it off. Had you gotten the right parts, you wouldn't have to go through all of this. You can get wet exhaust hose from most marine stores, just try not to get the wire wound hose if possible, it's not really needed and it's a bear to work with.<br />Try looking HERE for the exhaust options. Look at either the 1984 898 or 228 models and check all the exhaust links on the pages. Depending on the exhaust Y size and the elbows (not risers) you may find something to make your treasures work. Getting the right parts would probably be cheaper in the long run though.

 

[newport dave]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Stan,<br /><br />Unless I'm missing something, I think all you have to do is replace the old "3 inch that turns into 4 inch" hose with a straight 4" wet exhaust hose. Should be available through this web site or a local marine supply store.<br /><br />Also some raw water systems feed the manifold and riser, some just the manifold. But you will need to install hose fittings on the risers for the hose that comes from the thermo housing. You may need "restrictor" style gaskets at the riser / manifold.<br />Dave

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Sorry I asked Don...I see we are back to the "back yard engineering", or the "get by method" or whatever ....You ought to know by now I've got a darn good reason for everything I do....<br /><br />I gave $150 bucks a pair of like new, and I mean "like new" genuine Mercruiser center rise Manifolds and Risers.(not aftermarket).<br /><br />If there is a problem with using these manifolds and "doing it right" then let's hear it...Because I darn sure can't find "1st rate" manifolds and risers any cheaper....<br /><br />Thanks for the link...the "help" is appreciated..<br /><br />Stan..<br /><br /><br />Newport Dave......<br /><br />No you are not missing anything ...and you are exactly right.<br /><br />I was just fishing.... in case Mercruiser made a stock hose on one of the many models out there that was 4" x 4".. Since both of these are Mercruiser, I thought there was a chance...<br /><br />If not then I was just looking the information regarding what temp hose was needed to "do it right", with "cut your own hose"......and I thought I'd ask about the hose to the thermostat housing while I was at it.<br /><br />Thank you for the input...I'm going to break down both sets of my manifolds and see what kind of riser gaskets they have...I had hoped to find out without doing that ..since I'll have to order gaskets and then wait 3 days.<br /><br />I will, as you suggest hook up the hose to the thermostat housing...although I'm curious to know why some manifolds have a thermostat hose and some do not...<br /><br />Maybe I can find a water routing diagram on Mercruisers ...that would stop some of my fishing.<br /><br />Thanks for your help...Stan

 

[tommays]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

stan<br />its not a right or worng thing its how much work and money it will take to make a connection from the new units vs finding ones that bolt in place<br /><br />if you read some of other posts about doing this it is giveing other people quite a hard time doing what would seam to be a simple thing when orginal style parts could not be found<br /><br />tommays

 

[Lou C]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Just did some similar figuring on my old OMC. I have good manifolds on it now (only one season in salt) but they don't last that long here. I have the V-6 with the one piece manifold/riser design (only OE never made in the aftermarket). I looked at parts diagrams, and it does look possible to convert to the center riser 2 piece Volvo style ones used on the later OMC/Volvo units. Then I priced it out, turns out because of all the parts you need to do it, it is 300 more than the one piece units. So looked around and was able to find the one piece units even though they have been on national backorder for months. So I'll store em in the garage until I need em. I kind of like the one piece units in one way since there is no riser/manifold gasket to leak. 460 a piece though!! But can't stand the idea of ruining a perfectly good motor just to not change the manifolds. This one is still OE, going on 17 yrs old!!

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Thank you Tom...<br /><br />The money was the reason I'm doing this...I'll use the old riser, before I waist much time....Only one manifold was bad ..but I wanted to use the complete pair since they were like "new"...... I'm in these cheap enough to trim the extruding 3" appendage off with a band saw and use a straight 4" coupler....or scrap 'em if its hollow or something. Or just exchange one riser and replace the one bad manifold... These are new, they are cheap and I just thought they would be "better " than just replacing the one manifold in stock form. I can replace both manifolds and both risers for the cost of one manifold.....or not<br /><br />If I replace just the one, I could even sell what's left and it cost nothing for the repair...but I think I'll just keep 'em...something else will come up.<br /><br />I don't have enough information to say right now..I'll post the result when I get it done<br /><br />I can't find squat describing the function of the extrusion on the new style manifolds....<br /><br />Stan...<br /><br /><br />10-4 Lou...<br /><br />I really like the old Four Winns, they hold up a long time...That's the only reason I'm tinkering with these 2 I have ...they just turned out to be better boats than I figured they would be.....especially for what I have invested.

 

[Don S]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

You are looking at 2 different designs in risers, and you really don't want to cut the 3" end off the 4" riser. That prevents the water from going back into the engine which is the reason for the newer style of risers anyway.<br />Compare these pictures and don't cut them. Or you will ruin your engine.<br /><br />

<br /><br />

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Thank you Don...<br /><br /> I "really appreciate" that information..<br /><br />Best Regards...Stan

 

[Laddies]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Stan on page 552 of a 2005 Sierra catalog there is a picture of every thing you need apparently they didn't see any problem with doing it, the picture is in last years Sierra and NAPA calalogs also I haven't one hand to give you the page

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Thanks Laddies service..<br /><br />I'll look into that again ...but I think these manifolds are still different...if the kit is what I think it is..These are 4' risers and those are 3' in that conversion kit.<br /><br />Stan

 

[Stan's Customs]

Re: New Mercruiser manifold risers (nearly)...will they work on on 1984 exhaust?

Sorry...that should have read 4" and 3"(inch)....<br /><br />...and yes if the page number, 552, is the same on the internet catalogue, those risers arn't like mine...Mine are a little later model and stick out further....<br /><br />Thanks for the lead though...Stan