1978 Chrysler 75hp Outboard not running right

[jgruberman]

Hey all, new to the forums... Hoping this works out.

I have as the title mentions, model number 757H8D. Just got it free from a neighbor who couldn't pay anymore storage fees. What we have done so far.. Replaced the three spark plugs, put new gas in, and I ran half a can of seafoam in the tank. The issue... It sometimes, eventually starts after enough holding the key to start and enough cranking. When it STAYS running... It's loud but it idles. When I open the rear of the throttle body by hand, it accelerates and goes fine. However, when I accelerate from the throttle lever at the steering wheel, it almost immediately dies. I have it in a plastic tub of water as not to damage the impeller or anything.

I'm leaning to believe it has something to do with the timing or the distributor(where the plugs run to)... Sorry I'm a car guy and don't know all the right terminology for marine engines

I would love some guidance or suggestions for what to check or replace, or next steps. Hoping to get this running since it was free and I'd love to take it out on the water without fear of not being able to get it back. Thanks in advance!

 

[Tnstratofam]

:welcome: To the best forum on the web for all things boat related.

There is a sticky at the top of this forum that links to a video giving link and sync instructions for setting up your timing and carbs.

You should plan on replacing the fuel lines, fuel pump, and cleaning the carbs if the engine has set for a while.

Also if your bucket of water doesn't completely cover the water intakes you should get a set of motor flushers to use with a garden hose to ensure good water flow to the impeller.

Also change the impeller. It should be changed yearly.

 

[jerryjerry05]

DON'T touch the timing or any linkage.
Timing doesn't usually change unless YOU do something to it??

Sounds like the carbs might be gummed up?
​The Seafoam isn't needed in new fuel.(my opinion it's a waste of $$)
Do a compression and spark test.

Clean the carbs.

Like the 2nd poster said, use muffs or a really deep bucket.
The water needs to be over the cavitation plate by 3-4 in.
The top 2-3 post here have good tips and procedures.

Get a factory manual.

 

[jgruberman]

Having looked at the video, at 1:42, the cam was way off and the line was far below the roller so I adjusted that.

Also at 2:26, my ignition/distributor cap doesn't turn nearly at all, much less freely like that. I try to turn it by hand and something isn't letting it rotate...

Also, if I push the throttle lever forward, it doesn't open the throttle body on the motor. I can see it pulling on the lever on the bottom of the motor but it doesn't open anything. I stopped there since if I can't get WOT, then that's probably an issue.. I think

 

[jgruberman]

It seems that this white link going downwards is stopping the throttle linkage from opening completely or even at all. What is it? It's almost like a "lock" not allowing the throttle(gray piece) to open..

 

[jgruberman]

Sorry, had issues getting an image attached from my phone... Included the link in the post above also.

http://i68.tinypic.com/1z31ppw.jpg

 

[jgruberman]

I actually think I've researched that part to be the neutral stop arm... If that's what it is, why isn't it moving out of the way when the boat isn't in neutral?

 

[Nordin]

As the neutral shiftarm not moves away the gearcase is not in forward or reverse fully. Or the shift linkage is not proper adjusted.

Disconnect the shift and throttle wires from the engine.
Move the shiftlever arm all way down and turn the prop in the same time, look if the neutral shiftarm moves away for the neutralstop at timingtower.
If it does, then the shiftwire is not proper adjusted.
If not, the gearcase do not go into forward properly.

 

[jgruberman]

As the neutral shiftarm not moves away the gearcase is not in forward or reverse fully. Or the shift linkage is not proper adjusted.

Disconnect the shift and throttle wires from the engine.
Move the shiftlever arm all way down and turn the prop in the same time, look if the neutral shiftarm moves away for the neutralstop at timingtower.
If it does, then the shiftwire is not proper adjusted.
If not, the gearcase do not go into forward properly.

I did have to make some adjustments so the throttle lever at the steering wheel seems to shift better. It still gets a little stuck and eventually forcing it works, but I'm guessing I just need to adjust the arm down a teensy bit so it still engages, and doesn't get stuck at times. I still need to make sure the timing is correct.

I checked compression and it's Cyl1(top) - 90, Cyl2(middle) - 120, and Cyl3(bottom) - 100. Are these numbers bad?

 

[jgruberman]

Side Note: I've been watching videos on timing, and TDC and 32 and 36 degrees... but I'm still having issues grasping on how exactly to check the timing. I've watched the sticky video about Frank doing the checking for spark and know OF the adjustment screw coming off the distributor... but that's about it. Watched probably a dozen videos but still missing something in my head...