1970 Chrysler 85HP

[ewbish]

I'm new to the forum, first post here. I'm resurrecting an old 1970 Chrysler Sport Sattelite with a 85HP Chrysler OB, model 856HA. Boat and motor have been sitting for several years. So far, I've cleaned the carbs and put new plugs and a new prop on it (prop was spun), changed the lower unit lube, new impeller and ran it for about 10 minutes in a tank at low speed and at 24:1 initially. I'm using Pennsoil Synthetic at 50:1after the first start up. Compression test (cold) read just under 100lbs for each cylinder. Took it out to the lake for a test run, and it idles fine, and runs fine until about 1/4 throttle, where it starts misfiring and will not run out. I pulled the plugs and top two are very light brown and dry, in other words somewhat lean. The bottom plug was almost black. I took apart the fuel pump and the diaphram is extremely hard, and has some cracks in it, so I suspect this is my problem. I finally located carb kits for it, and have 3 on the way along with the new diaphram and a shop manual for the boat.

I have no idea what the point gap or the timing should be on this engine, heck I haven't even got a clue how to CHECK the timing on this engine (my 2-smoke knowledge comes from 30 some years of building engines on dirtbikes, very little boat experience).

In browsing the archives, it seems that many reccomend removal of the "bypass valve", is this true? If so, where is it located? Maybe something to do once I get it running right.

Any other suggestions on this motor? Any other ideas on the stalling/missing past 1/4 throttle? Am I on the right track with the diaphram and/or carbs? Thanks, and I appreciate any tips.

Eric

 

[eurolarva]

Re: 1970 Chrysler 85HP

Hello Eric and welcome to Iboats. Fuel pump is probably your problem. Does the boat have a fuel tank or are you using a portable 3 or 6 gallon can? I would get all new fuel hose on it including the primer bulb and the oring at the quick disconnect if you are using a portable tank. Chances are the fuel pump will take care of your speed problem. Everything else in your post looks like you pretty much have it covered. Points are .013 to .015 and firing order is 1,2,3. Carb kits and fuel pump kits are availible from NAPA as well.

 

[ewbish]

Re: 1970 Chrysler 85HP

Thanks for the answer. I'm using totes, and have all new fuel line and bulb. Replaced all the fuel lines on the motor as well.

Two more questions, I haven't timed an engine in over 20 years (god bless new technology), I dug up my old timing light and tried to check the timing. I see a marker tab on the front of the engine. I'm assuming I should be able to hit that with the timing light and see the timing marks on the flywheel--only I don't see any marks on the flywheel. Am I going about this wrong? It's been a long time, maybe I'm looking in the wrong place?

Secondly, I keep reading horror stories about this bypass valve and Chrysler engines, any insight? Where is it located and can it just be removed? Thanks,
Eric