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1970 CHRYSLER 70HP MAGNAFORCE IGNITION PROBLEM

S

squibs

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"Hi, just bought a 1972 phanto

"Hi, just bought a 1972 phantom boat. It came with a 70hp chrysler engine. The engine runs fine, but it has trouble starting. Sometimes the engine will backfire when it tries to start. It takes at least 5 tries, with priming, before the engine will start. When the engine does start, there is no problem. I have changed the spark plugs with b9hs-10 from cabelas and changed the spark plug wires. I have no idea how an outboard works. I bought the boat for $300, so I don't really want to spend much to fix the engine. Is there a simple way to fix this problem, or should I hire a mechanic to fix it."
 
"Any motor that has sat for a

"Any motor that has sat for a while will need attention. My brother in law has that same motor and it runs well. I suggest you do or have the following done.
1. Rebuild carburetors and syncronize the linkages.
2. Rebuild fuel pump (may be your problem).
3. Clean the points or replace them.
4. Replace the water pump. Don't take a chance on an unknown pump impeller. It's only rubber!!
5. Change oil in lower unit. If it is milky colored you will have to reseal the lower unit.
6. Buy a good maintenance manual for it.

Use Seafoam in the gas with the correct oil mixture. Seafoam will clean up the fuel system well. Get it at WalMart in the automotive section.
You can do all of this with basic mechanical skills and some help from the guys here.

Franz at Franz Marine is a good source for help as well.
Find him here:
http://www.geocities.com/thechryslercrew/

Bill"
 
One thing I forgot:

Before

One thing I forgot:

Before sinking a lot of moeny into it check the compression in each cylinder. Should be around over 100 psi and no more than 10% difference between cylinders. My brother-in-law's is 135 psi.
 
"Thanks for the help. I check

"Thanks for the help. I checked compression and each cylinder was 120psi. I had the carburetors rebuilt. Tried to start the engine and it did the same thing. Finally my friend told me to try another battery. I did and it started right up. He told me I had to trickle charge the battery when I wasn't using it. So, it starts right up now, but now I have a new problem. Is gas supposed to come out of the exhuast? I have the water hose hooked up to the engine, but I can tell gas is coming out with the water. Is that normal?"
 
Unburned fuel/oil mix is norma

Unburned fuel/oil mix is normal in the exhaust especially running on muffs or in a barrel. It should be mixed up with the cooling water discharged. I'd also rebuild the fuel pump. It's simple and inexpensive to do.

Even though you have it running I'd do a good tune up and replace the water impeller.
 
"Well, I finally had to take t

"Well, I finally had to take the engine to get repaired. At $85 an hour I found out that 1. the starter had a "loose bolt" which is causing it to draw double the amp to start, 2. The number 2 carburetor is flooding at idle, 3. all carbs are externally leaking at idle 4. the engine requires 2 cycle mix to run (i was putting regular gas in there), and 5. the fuel pump is going bad, so might as well replace it."
 
"Paul
by 2 cycle mix be you m

"Paul
by 2 cycle mix be you mean that you havent used a 2 stroke oil mix ie just run on neat four stroke,as if you have even for a short time it may have knackered the motor ie no oil on the moving parts."
 
"Yeah, i ran it for about 10 m

"Yeah, i ran it for about 10 min without the mix in the gas, but the repair guy took the engine apart and said it was good. he inspected the pistons, crankshaft, and piston walls. he said it was fine."
 
"wow thats good luck,coz norma

"wow thats good luck,coz normally its good night for the crank & pistons.

i put a non snythetic oil in my motorcross bike and the motor lasted 10 mins on normal road use.

now i always over oil & and by the best oil,as it cheaper than bores & pistons and depression !
steve"
 
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