Calling Chrysler nowledged

I have a problem with an old Chrysler model 7071 70 hp that I took apart and cleaned up and reassembled over the winter. I am having trouble getting the motor to idle in gear. I can get the motor to start good until I put it into gear, then it will not idle unless I have the throttle open about a quarter of a turn. The new parts in the motor are, gaskets, impeller, t- stat, needles and seats and by pass valve. Also crank seals and diaprahm for fuel pump. The fuel hose was new last year. I also have tried two different new primer bulbs that go soft while running at idle. The fuel connector fittings are also new. The gas tanks were both new last year one is a tempo the other a sea sense. It will idle if you keep the primer bulb pumped up, and runs great at WOT. By the way my compression readings are 120 120 118. Any ideas will be appreciated.

Re: Calling Chrysler nowledged

when motor trys to kill try choking it. If that makes the motor run better you are looking at a fuel related problem. I have read posts concerning defective seats and needle valves. You mention you have to keep priming the bulb to keep it running. This is telling me you have an air leak somewhere. Put clamps on all the fuel lines. Mixture adjustments on carbs should be about 1 turn counterclockwise from fully seated give or take a half turn. If you mixture adjustments are out like 4 to 6 turns you may still have partial blockage in the idle circuits in the carb. You may have to go back in there with a wire and some spray carb cleaner.<br /><br />When you replaced the diaphram in the fuel filter did you change the gaskets on the fuel seats? Check them out closely and see if you can see any broken gaskets in there without removing the press fit seats. Play with the springs and make sure they are working correctly.

Re: Calling Chrysler nowledged

Thanks for the information, I did not change the gaskets on on the fuel seats, they were not in the kit. I also forgot mention in the first post that I see air bubbles in the glass sediment bowl of the fuel pump form time to time. My boat is about 200 miles from here, I do go a couple of times a month however, those lakes in Kentucky beat anything around here. I do have a fuel pump from a 1979 chrysler 45 hp in my basement, does any one know if it would on this 70 hp? I also have hose clamps on every connection of the fuel line. I suspect the seal on those cheap gas tanks as the source of an air leak. I did use some Sea Foam in those gas tanks last year may be it affected those rubber seals on the swivel fittings on the tanks?

Re: Calling Chrysler nowledged

I think chrysler only made a single and two stage fuel pump. The single stage one is for the small engines. If yours has the glass sediment bowl and the figure eight type diaphram it should work on your 70Hp. If you choose to replace the fuel seats and gaskets here are the merc numbers. 21-F177330 is the fuel seats and they are about 5 bucks each. 27-F84792 is the gaskets and they are about 50 cents each. One of the press fit seats is a bear to get out without breaking it. I just replaced all three of mine. At least check the middle one. It is held in by two screws.<br /><br />You might also want to check your reeds and make sure they are okay.<br /><br />Good luck

Re: Calling Chrysler nowledged

Thanks again for the information, is there anywhere I can get my hands on the parts cross reference numbers form Chrysler to Mercury? I looked at the at the reeds when i had it apart last winter there was only one reed in the #2

Re: Calling Chrysler nowledged

I accidentally hit enter, and did not get to finish my reply, any i had only one reed that i could see any light through and it was just a little bit, probably less than two or three thou of an inch. If the fuel pump wasnt working properly wouldnt it run bad at wot?<br /><br />Thanks again.

Re: Calling Chrysler nowledged

I go here for merc parts merc parts. My motor is 1967 but I use this site for the blow ups. If the part looks similar I go ahead and order it. I have had pretty good luck. Another good place for parts is ebay. Too bad it is hard to find parts for these older motors. They have some quality parts in them and are pretty easy to work on.

Re: Calling Chrysler nowledged

Awesome site, I have only been doing his for about two years and this is the best site I have found yet. I agree on ebay, i have bought a few items there including this motor I am currently working on. I think it is just as fun tinkering with them especially in the winter. I also find Chryslers easy work on especially with this site. And the horse power to weight ratio is good too. I am going to call a place here locally that has alot of old Chrysler stuff and see if he has those fuel seats and gaskets. He cant get to my motor for two weeks and I am leaving for a week on the lake on friday.I will stop in here when i get back and let you know what fixes it.

Re: Calling Chrysler nowledged

Just wanted to let you know that after replacing two of the fuel seats and gaskets, This old motor ran good. Thanks all, for the help this is my favorite site on the web.

Re: Calling Chrysler nowledged

Thanks for the follow up post. Lots of people post problems but once they get them fixed some of them never let us know what the problem ended up being. Good luck with the motor and have fun.