'72 Chrysler 85HP Outboard

[scotiany]

Re: '72 Chrysler 85HP Outboard

When you turn the carb upside down, the float should be level with the bowl flange. When it's in normal position, it should drop 13/32 from flange to top of float.

 

[oslo]

Re: '72 Chrysler 85HP Outboard

I installed the new parts today and the engine starts but it sounds as if it's running on two cylinders. I did a compression check again and its reading 1)120 2)120 3)125. Before I removed the head it was 1)135 2)135 3)150.. I torqued the head bolts to 15LB then 20LB from the centre outwards in a hex sequence. I used a palm sander with 120 grit sandpaper to clean the head. Should I have used permatex gasket sealant on the head gasket? How many milimetres are in 13/32?

 

[The Marine Doctor]

Re: '72 Chrysler 85HP Outboard

No sealer is to be used. You will have had dry cylinders when doing the test. The comp should rise. I see they are more even now.<br /><br />Generally scraping is a better method to remove gaskets on aluminum as it is a soft metal.<br /><br />As for the mm I think roughly 12-13mm.<br /><br />TMD

 

[oslo]

Re: '72 Chrysler 85HP Outboard

I ran the boat on the lake today, and the bogging down has stopped. The engine idles a bit high. I tried to lower the idle speed but it is at its max. The idle bolt doesn't touch the engine block and it's still high....when I rev the engine from the carbs throttle it back fires once or twice on its accent and a lot/repeatedly on its desent...........I'm using a slightly hotter coil and I did not replace the old points just in case the coil fried it.

 

[The Marine Doctor]

Re: '72 Chrysler 85HP Outboard

Hi Defender...try opening the carbs a slight bit more. It sounds like its running lean as it idles down.<br /><br />As for the idle screw..something is out of whack. You probebly do not have the throttle butterfly's in sync. Disconnect the throttle actuator. <--at the plastic coupler. Looses the 2 small screws on the throttle plate tower. Let the throttle plates fall free....then retighten and hook the actuator back up.<br /><br />TMD

 

[oslo]

Re: '72 Chrysler 85HP Outboard

You were correct again TMD! It was the throttle plate tower. The top carbthroat was slightly open. THANKS!<br /><br />THE NEXT PROBLEM....I adjusted the airmixture screwes to one full turn from the shut position. The engine idles great, the back firing has stopped. It just sounds muffled, not as responsive when I rev it. I think the engine had that symptom a couple of months ago when I tried the gapless plugs. Analysis please....

 

[The Marine Doctor]

Re: '72 Chrysler 85HP Outboard

Are you reving it with the shifter or just with the throttle cam? If you are just using the throttle cam, this does not advance the timing.<br /><br />It is also possible that only one carb was causing the pop. You might try to find out which one and just let it have the extra fuel. This might take care of the muffled problem. Generally caused by a rich condition.<br /><br />TMD

 

[AtlDawg]

Re: '72 Chrysler 85HP Outboard

Hey let me jump in here with a question. My factory manual doesn't show good pics of the Tillotson carbs. I thought the adjustment screw on the back(with the adjustment hole for a screwdriver in the carb cover)was the idle mixture. Is this the air mixture for higher rpms as well? I didn't see any other adjustments for mixture or anything inside the carbs other than the float tabs. Am I missing something? My carbs are from a 73 70 hp 707HF.<br />Thanks

 

[The Marine Doctor]

Re: '72 Chrysler 85HP Outboard

The only adjustments you can make on a Chrysler carb are for low speed air/fuel mixture.<br /><br />If you need more or less fuel for WOT you must rejet the carb.<br /><br />TMD