Carburetor Swap: 1991 E200CXEI carbs on a 1988 E225CXCCE

[Greg_E]

I'm in the process of reassembling a 1988 V6 225 HP Looper. I used the carbs from that motor on another engine. I have a set of carbs and throttle bodies from a 1991 200HP. Can I make the swap with no other modifications to the carbs? Obviously I will loose some HP using these carbs. That doesn't concern me as long as it will run right.

 

[ondarvr]

Check the parts diagram for each one and compare the numbers for each part, this will let you know the exact differences.

 

[Greg_E]

Check the parts diagram for each one and compare the numbers for each part, this will let you know the exact differences.

Thanks for the reply but it gets a little more complicated than that. They changed the the part numbers on the carbs and throttle bodies every year from 1988 (1st year for the big bore V6 looper) up until I think 1993 when OMC finally found a combination that worked. You can't really compare year to year because they were constantly changing carb bodies and orifice sizes. Add to that the fact that these carbs were from a 200 HP engine and it is pretty much impossible to make any sense out of it looking at part numbers. What I need to know is, can I use the 1991 TB's and carbs, wind up with a 200 HP engine that will run properly without changing any of the fuel and air metering components in the carbs? I don't want to be lean on fuel or oil.

 

[jimmbo]

Can I make the swap with no other modifications to the carbs? Obviously I will loose some HP using these carbs. That doesn't concern me as long as it will run right.

To answer both questions... Maybe, maybe not. Are the carbs the same size, venture and throat wise. Throttle plates, off idle circuit, air bleeds, jetting may be different. They maybe exactly the same carb, with the HP differences due to porting and exhaust changes. If not and the calibration is wrong, it may result in a damages engine. If the carbs are smaller and the calibration is acceptable, Hole Shot should be better

you are going to have to be read the spark plugs to see if the mix is too rich or lean at WOT
As for ending up with a 200hp? Again depends on the porting, reeds, intake manifold, and exhaust tuning. Any of them could different. Service parts lists show what is replacing the old part. it may not show what was different at time of manufacture.

 

[ondarvr]

Check the other aspects of the motor, block, heads, etc. They did a lot of mixing and matching to get different HP ratings, so you may see the block (porting) is the same for the 225 and 200 of each year with different carbs, or something similar.

 

[Greg_E]

Thanks guys. I'll check some of the items listed and report back. The intake manifold is listed as the same for both years and models. I'll see if I can find a part number stamped on them. I have both to compare. I don't have the 1988 carbs here to compare the venturi and throttle bore diameters. The carb body part numbers are different between the 1991 200 and 1991 225 and also different than the 1988 225. The part numbers may just be different due to the air bleed orifices being different. (I'm making the assumption that the carb body is sold complete with those parts installed which may not be the case.) I'll need to look into that further.

 

[Greg_E]

OK. I've done a part number comparison of everything I can think of that could be different between the 1988 225 and the 1991 200 as relates to this swap.
Cylinder case, heads, crankshaft, piston rods, pistons, intake manifold, and reed boxes are all the same. If I haven't missed anything the only difference would be the carbs and throttle bodies, so I should be able to use the 1991 200 carbs and TBs as is, and have a 200 HP engine. The carbs and TBs for the 1991 225 are different part numbers than the 1991 200 so once again, the only difference I can find is between the 1991 200 and 225 are those two items.

Feedback appreciated.

 

[ondarvr]

Sounds promising.

 

[Faztbullet]

Vent the bottom bearing like the newer motors and bolt on and go....

 

[Greg_E]

Vent the bottom bearing like the newer motors and bolt on and go....

I've already done that modification, a tip you gave me some years back. Thanks again.
Thanks to everyone that replied. I was pretty sure I could make the swap but it's nice to know for certain.

 

[Greg_E]

I ran into one small problem but I don't think it's an issue. The plastic link for the port and stbd throttle body shafts was broken when I got the 1991 carbs. No problem. I have one from a 1988 that looks like it will work but there are some differences. The metal parts that connect the link to the two TB shafts are slightly different and the 1991 link is a two piece with an adjustment spring between the two halves. The 1988 is a one piece link. Also the cam follower is smaller on the 1991. I think the 1988 link will work because the throttle cam is the same for both years. When I operate it manually everything seems to move in unison. Just thought I'd check to be sure. I am going to need a new cam follower. the two I have for spares are flat spotted and they have already been flipped end for end.

 

[jimmbo]

One of the joys when one constructs a FrankenRude

 

[Greg_E]

I did some more checking. The part number for the 1988 link was superceded to the 1991 part number and then two more times to the final 0435908 part, none of which are available new. The 1988 link will be fine. It looks like the two piece design allows for some link length adjustability for fine tuning the throttle plate positions between the two banks. Also post #11 should read adjustment screw, not spring.

I ran into one small problem but I don't think it's an issue. The plastic link for the port and stbd throttle body shafts was broken when I got the 1991 carbs. No problem. I have one from a 1988 that looks like it will work but there are some differences. The metal parts that connect the link to the two TB shafts are slightly different and the 1991 link is a two piece with an adjustment screw between the two halves. The 1988 is a one piece link. Also the cam follower is smaller on the 1991. I think the 1988 link will work because the throttle cam is the same for both years. When I operate it manually everything seems to move in unison. Just thought I'd check to be sure. I am going to need a new cam follower. the two I have for spares are flat spotted and they have already been flipped end for end.