Hard start 1980 85 horse Chrysler

[bashr52]

I started having an issue with my engine at the end of last season. Now that the boat is back in the water, the problem persists. The primer bulb stays nice and firm, even after the boat has sat for a week or two. If I try and start the engine with the controls in the start position, choke on, it will just crank with no fire. If I manually hold the choke closed and butterflies open with the throttle in the start position while someone else cranks, it will start and run within 2-3 revolutions. Once it has fired up, I can shut it off and it will start every time with a single turn of the key. Within the last 2-3 seasons I have gone though the whole engine and either rebuilt or replaced the fuel pump, all 3 carbs, reed set, intake gaskets, cleaned low speed re-circulation circuit, etc.

Any thoughts/suggestions?

 

[SkiDad]

choke solenoid working ?

 

[Tnstratofam]

Are the choke butterflies fully closing when the choke is applied? Have you synced the carbs?

 

[Jiggz]

It's obviously a choke problem. With the cowl removed, try starting it again while at the same time closely watching the choke mechanism. It's never unusual to see (and hear that click) the choke engages and then disengage as soon as the starter engages. Both starter and choke coils are on the same circuit and if the battery is a little old and weak (or lower CCA rating) the choke starves out of power and disengages not to mention that the current has to go through the length of the boat because of the location of the ignition switch and back. This presents a high resistance to the choke circuit while the starter is virtually a short circuit due to its very low resistance. And since electricity always take the path of least resistance, the choke circuit losses power.

I had the same problem with my 89-125HP. So I placed in a mod using a 30A relay to energize the choke coil straight from the battery using larger wire gauge. With this mod, the ignition switch only energizes the relay (with very little power requirement) while the relay connects the choke coil straight to the battery. Never had choke problems eversince.

 

[Frank Acampora]

The older 3 cylinder Chrysler engines had gaskets between the airbox and the carb fronts. These gaskets would occasionally swell and jam the choke stop levers. If the chokes are not closing with the key check these gaskets and cut away any interference, You should hear the choke click closed. If you do not hear this, check the solenoid and the switch.

 

[bashr52]

The choke works as it should. I get an audible click with the cowl on and energized, and can see them close fully with the cowl off.

 

[Frank Acampora]

Please describe your start position. Some of these engines are very fussy and will simply not start cold unless the throttle is advanced. Are you pulling out the shift disable lever or pin and advancing the throttle as far as it will go?

 

[Jiggz]

The choke works as it should. I get an audible click with the cowl on and energized, and can see them close fully with the cowl off.

With the cowl off and with the starter engaged, the choke stays close? I understand you said you can see them fully close with the cowl off but do they stay closed when you engage the starter? In your original post, why do you have to manually hold the choke butterflies closed if they actually work and stays closed as you mentioned?

 

[bashr52]

Frank,
The start position is the knob pulled out and the throttle advanced as far forward as possible. With the cowel off, all the seems to do is advance the distributor slightly.

Jiggz- yes the chokes stay closed when cranking. If I crank the engine with the throttle in the stat position it will just crank and no fire, even with the chokes closed. If I put the throttle lever in the start position, key on, manually hold the butterflies open and chokes closed, and crank the engine by shorting the solenoid across the B+ post and starter wire (I have made up a push button with clips to do this), it will fire off within a few rotations and die. Once it has fired once though, I can simply turn the key to start and it will run without issue.

It seems to me the issue may be with the throttle position at start. Perhaps slack in the control cables is no allowing the distributor/carbs to advance/open like they should?

 

[Frank Acampora]

Perhaps the carbs are not opening correctly. In the fast idle/start position the carb butterflies should crack open and the distributor advance only a couple of degrees. This will allow the engine to start and warm-up at somewhere around 1500 RPM. If the carbs are not synchronized to the timing it is possible that they are not opening correctly. Even if there is compliance in the control box or control cable, the carb opening in fast idle is regulated by the stop built into the shift linkage and the control tower. A warm engine in good condition with clean plugs should start quickly in neutral with the carbs completely closed and no choke so you are good there..

SO: Try this. Go to the video of synchronizing timing and carbs at the top of the forum. Synchronize your engine according to the instructions and see if that helps the problem.

 

[Jiggz]

Well if the choke butterflies are verified to stay close during cranking then maybe the problem is with the throttles. The only question is why does the engine starts normally as soon as it gets warm? Which would indicate the idle position of the throttles are set correctly. Or could it be the fast idle position is not actually correct as mentioned?

 

[bashr52]

Well if the choke butterflies are verified to stay close during cranking then maybe the problem is with the throttles. The only question is why does the engine starts normally as soon as it gets warm? Which would indicate the idle position of the throttles are set correctly. Or could it be the fast idle position is not actually correct as mentioned?

Jiggz,

It's not so much the engine starting normally when warm, it starts normally after I get it to fire off the first time by manually working it chokes/carb butterflies. It acts like I just need to prime the system, once it fires off once it will work fine. The first time I start it manually, it may only run for 3 seconds or so before it dies, but them will start and run forever even with the key after that.

I'm really thinking the issue is in the start/fast idle position, since the only thing that happens is the distributor advances a few degrees and the carb butterflies do not even twitch.

 

[Tnstratofam]

Your distributor will only advance a little when you have the shift dissable button pulled out and the throttle pushed forward to the fast start position. Your distributor won't advance far because the distributor timing tower is tied to the shift linkage and with the shift linkage dissabled it only rotates forward a little. Your carb butterflies should open though so if you aren't seeing them open I believe your problem is the carbs and butterflies are out of sync. At the top of the Chrysler forum page is a sticky that Frank has posted with a link to his youtube video that has detailed instructions for the home mechanic to link and synk as well as time theese engines. I would follow theese instructions and start there. I believe from what you are describing this will aleviate your hard starting condition.

 

[bashr52]

OK update from the Holiday weekend. I re-did the lync and sync following Frank's instructions, no change. One other observation I made however is when I first got up there I tried to squeeze the primer bulb it was super firm. Watching my fuel filer nothing really was forced in as I squeezed the bulb. Perhaps the problem is not with the engine, but rather not being able to prime the system? The engine did start right up and ran fine all day once I got it going by doing the usual and holding the choke closed and throttle wide open with the dist advanced to the start position. Once it starts, if I shut it down I can get it to fire off again with a flick of the switch. It doesn't even go through one whole rotation before it fires off.

 

[Jiggz]

There you go again, " . . . holding the choke closed and throttle wide open . . ." If the choke stays close why do you have to hold them closed manually.

 

[bashr52]

There you go again, " . . . holding the choke closed and throttle wide open . . ." If the choke stays close why do you have to hold them closed manually.

I only have 2 hands . I keep the chokes close and butterflies open with my left hand and work the starter with my right while standing in the back of the boat. I can't reach the key and engine at the same time.

 

[Jiggz]

I see. But if you keep doing the same troubleshooting you will never be able to eliminate the cause of the hard starting. You might want to get a second person to do the starting or holding of the throttles. Or if you do not have second person, use a rope so you can hold open the throttles while using the ignition switch to activate the choke and start it. In short, this is the process of elimination:

1. Hold the throttle open while letting the ignition switch activate the choke and start the engine. Does it start? If yes it means it is a starting throttle problem meaning you need to check the fast idle position of the throttle with reference to the control lever when placed in fast idle.

2. From the preceding, if the engine will not start with just holding the throttles open, try leaving the throttles in their fast idle position but this time hold the choke down closed manually, Does it start? If yes, then it is a choke problem. If not then it must be a throttle starting position problem.

With the two steps above you should be able to eliminate which of the two, throttle start position or choke, that is causing the cold hard starting.

Keep us posted.

 

[bashr52]

Weekend update: I spent some time Saturday going over everything again. New fuel line to rule out primer bulb issue (stayed too hard to prime), new set of plugs, checked timing, etc. I verified the carbs are all getting fuel when primed, spark is fine, chokes working when cranked. There was no change, I still needed to hold the throttle plates open with the chokes cold to get it to fire. I have a theory however. It appears the engine vacuum while cranking is being stopped by the throttle plates instead of being drawn against the choke plates and drawing fuel into the system. This would explain why holding the throttle plates open and chokes closed allows the engine to fire off right away. Now I need to just determine if it is a low compression issue or incorrectly adjusted throttle linkage. I did a link-and-sync a few weeks ago but the aftermarket reed assembly I have installed may need more adjustment than normal?