100HP Chrysler 1979 Model 1007H9A - Carbie covers

[MickLovin]

Hi all I am looking for 2 plastic carbie covers, I can't see them in a parts list so I am unsure if this model came with them or you can get some to suit from another hp model.
If you know of any available please let me know as i have scoured ebay etc looking for some.

 

[Boatdoc58]

Re: 100HP Chrysler 1979 Model 1007H9A - Carbie covers

They did not have the covers you are talking about that year.

 

[Frank Acampora]

Re: 100HP Chrysler 1979 Model 1007H9A - Carbie covers

I believe the 100 HP engines came with WB carbs , not the much larger TC carbs to which were mounted the plastic covers.

HOWEVER: If it is important to you to cover the carbs, the cylinders and carbs are the same distance apart as 3 cylinder engines so you can use the airbox from a 70, 75, 85, or 90 three cylinder Chrysler or even an 85 Force.

 

[MickLovin]

Re: 100HP Chrysler 1979 Model 1007H9A - Carbie covers

I believe the 100 HP engines came with WB carbs , not the much larger TC carbs to which were mounted the plastic covers.

HOWEVER: If it is important to you to cover the carbs, the cylinders and carbs are the same distance apart as 3 cylinder engines so you can use the airbox from a 70, 75, 85, or 90 three cylinder Chrysler or even an 85 Force.

Thanks Frank and BoatDoc, I did think about putting my old 75hp carb cover on and just blanking out the centre carb position, any idea where I would take the residual fuel which is hosed to the top of a 3 cylinder, could I just tee it off with a similiar hose on the 100hp or would this change the fuel system scavenging cycle? I would also have to drill out the carbs to take the screws for the 75hp cover, any idea what size the screws are, I have them but no gauge to judge what size and I know they are imperial not metric.

Could I also ask, are the 100HP carbies jetted bigger than the 75hp to allow for the 2 cylinders they feed rather than the individual cylinders in the 3 cylinder. It doesn't seem to have this in my manual.

I was getting fuel directly through my crankcase and flowing straight into my tub of water which my motor was in, it was quite a bit and considering I had just bought the motor I did initially panic. But after further study and inspection, it was the fuel pump diaphram which is operated by the crankcase (pressure or exhaust not quite sure here), which had a rather large hole and cracks, replaced the diaphram and away she went, not fantastically at first as I had treated her with a de-carbon. I stopped the motor, took the plugs out and let her pump out the old fuel which had gummed up the crank, then restarted her and she fired like a dream, just a water test now after cleaning and resyncing the carbs as per Frank's instructions ( Thank you Frank) although I already knew how to do them from your original vid and Mr Garnetts vids on Youtube. Just so you know frank I am a Chrysler Fan and also a fan of your vid .

Any way what I haven't said is, when I bought the motor he lifted the cowl and it was like showroom condition, not a scratch or sense of corrosion due to fresh water use, the compression was also in the spec range of 130 - 140 which you would be lucky to get for a 44 year old motor, it still had the original cable tie on the choke and the original metal water flusher from Cleveland US.

Could you also advise if my 75hp 1980 model prop would suit my 100hp motor, it is the same gearbox and shaft they only thing id be concenred about is the pitch. my 75hp model prop has been balanced and is Stainless steel unlike the 100hp.

Did Chrysler change gear boxes after 1978? My 1976 75hp gearbox is different and aren't interchangeable.

 

[Frank Acampora]

Re: 100HP Chrysler 1979 Model 1007H9A - Carbie covers

Yes, after 1978 Chrysler developed the one piece lower unit. It was much more efficient yielding an average of 3 MPH more. There are also a wider selection of props available. The old pin drive props for the two piece lower unit are no longer available new and must be found used on ebay.

The 100 HP carbs are jetted larger to allow the greater amount of fuel the 4 cylinder engine needs. Not only are they jetted bigger, the venturi is larger 100 HP has 1 5/16 inch diameter while 75 has 1 3/16 diameter.

Carb front flanges should be drilled 3/16 and tapped 1/4 X 20 to receive the airbox mounting screws. If you want to buy new, use the metric equivalent--11 MM head bolts.

If you do use the 3 cylinder airbox, spit back fuel can be recycled to the lower or upper. The upper is better because there is a flat on the side which can be drilled easier, HOWEVER: You must use the fitting on the bottom of the three cylinder engine manifold. This fitting has a metered orifice so that it will not go lean if there is no spit-back fuel available. This fitting is a 1/16 NPT thread. You could use a brass fitting of smaller thread and tap the carb flange--this would eliminate the need for a metered orifice but you would need to adjust that carb's low speed needle a bit richer to compensate for possible air bleed at idle.

The 1980 prop will be a 15 spline prop and should fit the 100 HP engine. However, with horsepower ratings, prop size is all about hull size and weight AND prop pitch. If the prop pitch allows the 100 HP engine to rev up to 5000-5500 RPM at full throttle, then it is correct.

 

[MickLovin]

Re: 100HP Chrysler 1979 Model 1007H9A - Carbie covers

Your the man