1978 chrysler 105hp ignition problem (restoration project)

[jmuff24]

Hi I own two 78 105hp chrysler motors one on a fin and fun the other on my most recent retoration a conqueror with same motor.
The fin and fun worked great until it had a bolt co e lose on the roller and went through block. The conqueror was short only a starter so I swapped it from boat 1 as well as the carbs and replace all fuel lines and spark plugs and re did all wire ends and clips and have double checked all connections. I have good compression but have no spark. I swapped out the wires and stator from the fin and fun which I know worked butnstill no spark. Only thing I havent changed is my fin and fun had a rectangle white box on the stator with a long fuse looking item inside of it that was tied in to the ignition spot and the other lead going to the negative on the stator. The conqueror just has a cylinder shaped item with one black lead going to the negative of the stator. Not sure if this could be my issue or if the part the wires attach to that has the shaft that goes up to a belt to the main shaft needs to be replaced. If this makes any sense pleaee help lol. Im trying to get this boat back in operable condition and im kind of at a loss. Been reading on updated conversions but not sure if I can do it for my motor or how.

 

[Nordin]

Re: 1978 chrysler 105hp ignition problem (restoration project)

jmuff24 please attach some pics so we can se what ign.system you have.
During that time the 105Hp could have the Motorola beltdriven MagnaPower system, MagnaPower II or the Prestolite MagnaPower system mounted.
The parts you are takling about that are differnt on you 105Hp sounds to me to be the noisereductioncapacitor, but please add pics and you will have more chance to get help from this forum.

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Okay i will in the next 30 minutes pretty positive its belt driven

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Okay got it started....was the points they were new but the prior owner didn't gap them I over looked that careless mistake so put new ones on. Started right up....now next issue....she's running pretty good I know my fuel mixture may be some of this issue. But here we go.....okay I have it idling at what I think is good I can't find the proper gap for my contacts I thinkbi had seen someone say .014 and that's what I have them at but when I idle it up to full theottle I'm getting backfire a lot. I've tried messing with the air jets on carbs which inhave no idea where their SUPPOSED to be but think their close.

So once over my questionn is could the backfire be because I have the wrong contact gap and if so what is proper gap....or .....could it be carb related or could my coil need upgrading or replaced?

Last question not AS important since I have it running and points are abundant to get down the road but what kind of HEI system do I need what's the part number so I can order one later... like I said not as important I want it running smooth first.

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

If you have a distributor, you have a Motorola capacitor Discharge ignition system. Backfiring can be incorrect timing or too lean a mixture.

Timing should be set to 30 degrees advance at wide open throttle. low speed mixture screws should be set starting at 1 to 1 1/4 turns out from lightly seated.

Watch the tutorial at the sticky at the top of the forum and read synchronizing timing and carbs in the same FAQs,

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Okay I watched the videos on checking timing and fortunate enough mine still has all marks and YES timing is set perfect belt is good butterflies are good. I resetthe air jets as said pretty sure that was my problem because they wwe're backed pretty far out. I also saw where you had posted a reply to someone epse frank saying the gap for point is .10? Or is it .14? I have mine set at .14 at the moment may try the .10 if what I've done to air jets doesn't work. I still believe my fuel may have a large part of the issue so I plan on using a can of true fuel 50:1 today to make sure everything is set properly with no possibility of fuel hindrance.

Question 2... is there any step by step to remove a lower unit to check impeller? (Have never removed a lower end..ever) where can I purxhase an impeller?

Question 3... oil change... is the fill and drain plug the one with flat head on bottom of lower end? And do I have to have a electric pump to do an oil change?

Anx frank do you know where I may be able to buy more distributor caps? I wouod like to stock up on a few I'm thinking of upgrading my coil

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Point gap should be between .009 to.011. Thus, try for .010.

Distributor caps almost never wear out so unless yours is broken or compromised, don't bother to buy an extra. They are very expensive too so you are better off salvaging one off a junk engine--any four cylinder distributor ignition.

If you simply must have a new cap, try franzmarine@aol.com same if your impeller is from a two piece lower unit.

Now, if you have a 2 piece lower unit, the prop will have a thrust pin under the tail cone. These engine only have two fill/drain plugs. you set the engine to vertical and remove both plugs to drain. These screws have a large slotted head, about 1/2 inch in diameter. DO NOT remove the screw on the side of the gearcase bullet This screw is recessed and has about a 3/8 diameter head.

To fill, you buy marine grade lower unit oil and a pump. pump through the lower hole until oil issues from the upper. Then, replace the upper screw and work quickly: Remove the pump from the lower hole and replace the plug. It is better but not necessary to use new gaskets. However, be certain the gaskets are still in place and tighten the plugs with a large flat blade screwdriver.

The one piece lower unit has a thrust washer behind the prop and water pick-up slots on the gearcase side, just behind the prop. It has three screws that you remove to drain the oil. Again, do not remove the small, recessed, slotted screw. These lower units have three different type drain screws: A slotted, stainless pipe plug under the front of the bullet nose, a plug the same as the fill and vent plugs, either under the nose or on the side of the skeg, or a small set screw under the bullet nose. Remove all three plugs to drain. Then replace the drain plug. using a pump, slowly pump in oil through the fill hole until it issues from the vent hole. Let the engine sit for 15 minutes to let any entrained air rise and top off the oil. Replace the plugs.

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Okay thanks for the gappi g info I have set it to .10 for the mean time....I reset the air jets to where you mentioned above...I pulled off the lower unit to check impeller today and it was trashed so I swapped out lower units from my other 78 105hp and checked everything on it all was still good...soaped the impeller and stuff some and gresed my shaft and cleaned lower unit up. Now..

When the motor is idling. ?..I see the pin hole on the lower unot above where it sucks water from pouting out a good solid stream but doesnt seem like I have much water coming out of the telltale unless I idle it up some...is this normal or does it have to be in gear for it to come out of the tell tale on the leg?.
Okay and secondly back to my other issue...idol is a lot better but now when I go to throttle it up it backfires bad now versus prior to resetting gap and air jets it didnt baxkfire until it was almost WOT......still could be fuel though? Plugs were a little fouled up when I pulled them today except number four...it was clean as new almost....good or bad?

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Oh and by the way to anyone else using my thread or reading it the other thread form78 chrysler 105hp impeller change was step by step and very helpful and quick...im a decent mechanic but had never messed with a lower end unit before....im pretty sure that step by step was posted from Frank above....thanks again for all the help!!!!

 

[jmuff24]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Okay issue now....pretty sure I AM NOT getting proper water flow....I changed imeller...changed lower end with one I know works and is clean changed thermostat cll grommets and gaskets and seals are all good...only thing I could think of is a piece of the ood impeller or something made it up towards the block...?? How wouod I flush it BACK out WITH OUT taking off powerhead? Or is this possible? Was thinking I couod maybe remove lower unit again and remove thermostat then spray water down thermostat tube to hope flush anything out? Good idea or bad?

And I'm still having issues with it baxkfiring or missing when I throttle up now my guess is ithas to do with air jets now since it wouod idle up fine befor until I was WOT..mi reset them like frank mentioned above I'm assuming may need to be adjusted some more but I don't wanna mess up the block...going to recheck compression tomorrow again since motor got hot today while trying to figure out water flow issue....really hoping I didn't screw it up paint turned color and white sricker with wiring labels is now black....still starts and purrs when it idols though.

 

[C5Paul]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Question for you guys...we are working on a Chrysler 105 with ignition failure as well. Since my company designs and manufactures ignitions for motorcycles and cars (and 4 stroke boats), we figured on making a replacement kit for this beast.

I am trying to find the stock factory ignition curve, so i can program our system to match. How would i go about that?
We typically see two strokes with an aggressive low rpm curve, then pull back when it "comes on the pipe" but have no clue on outboards...we usually make kits for things that use tires.

Any help would be appreciated.

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

There is no ignition curve. Timing advance is strictly manual, no advance springs or counterweights and no vacuum advance or retard.

As you advance the throttle, timing advance is almost linear (with distributor engines) until just before full throttle when the "overcentering" retards timing a degree or two. There is no overcentering of triggers on non distributor ignitions. The throttle cam is curved to open the throttle(s) very slowly, reaching about 1/4 of their total opening at about 3/4 of control handle travel (cruise or economy position) when timing is fully advanced. The last (about 1/4) bit of control handle travel fully opens the carb butterflies. The engine makes a lot more noise, uses a lot more fuel, and the boat only goes 2-3 MPH faster (depending upon hull and engine combo.

Quite frankly, unless your company can do it on the cheap, I see no real market for a replacement ignition system and I don't believe you would be able to recoup development costs. You do have competition. CDI already makes replacement parts and older Chrysler engines can be retro-fitted with mercury ignition systems.

 

[C5Paul]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Technically if timing starts at one point (idle) and advances to something else at full throttle, that would still be considered a "curve". What we dont know yet, is how many degrees BTDC it starts at, and where does it end up at full throttle?

I understand there is no pull back of timing, due to the distributor being directly linked to the throttle, but we are electronically controlled using twin optic beams, so i can program it to have 100 degrees of advance if i thought that was correct (which i am pretty sure wouldn't work...lol).

Right now we just want our boat to run. If we decide to market it, there are so many advantages our ignition brings to the table that a Mercury or other replacement ignition doesn't have, but we are not interested in boats at this time except for vintage Chris Crafts with Hercules engines.

Multiple sparking at all rpm, light beam accuracy, and infinite creativity to build curves are just a few reasons it could be a success. We have no real development costs because our ignitions were designed to be a universal fit, and can be programmed in minutes for almost any configuration.

Chrysler lovers might find big increases in fuel efficiency worth the extra few bucks.

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Technically-smectically! Timing is mechanical and a straight line. Yes, TECHNICALLY a straight line is a type of curve but I am trying to help you and you are getting smart with me.

Timing at idle is not set and really depends upon the setting of the timing adjuster up top of the timing tower: These engines are timed at 32 for older Chryslers, 30 for newer Chryslers and Force at wide open throttle. THE ONLY IMPORTANT SETTING is wide open timing.

NOW: When the engine is brought back to neutral, idle speed is set by adjusting the idle stop screw. Idle speed, in order to prevent stalling when the engine is put into gear, MUST be 700-750 RPM IN FORWARD GEAR, IN the water. NOW: Since different pitch props will load the engine more or less, the idle stop adjustment will be different for different engines and even a different pitched prop on the same engine.

Since timing is mechanical and since it is set at wide open throttle, there is NO specific setting for timing at idle. I can tell you that from experience it typically is somewhere around 0 to +2 degrees advanced.

Also note again that as I said above, there is overcentering on distributor engines. This means that as the linkage moves the distributor, timing will advance a degree or two past the wide open throttle position. As the timing tower moves fully to wide open throttle, you can see the distributor back off a small bit. I know it is there but since these engines are almost never run in this throttle position, I never measured the retard. I simply set the timing to specs at WOT.

If you simply want your engine to run: Watch the tutorial again and read the sticky: Synchronizing carbs and timing. Run a compression test to be certain that internally the engine is healthy. THEN, pretend that everything that can be out of adjustment IS. Reset everything to specs. Understand that since it is a mechanical system, everything is related and a change in one setting affects everything else. THUS:

You can not get where you are going without knowing where you are starting. Therefore as shown in the video and explained in the sticky, set everything to the zero starting point before messing around with timing or carbs. Do it right or do it wrong--It is that simple.

Once the engine is running (assuming a good ignition system) THEN start screwing around with your aftermarket system.

 

[C5Paul]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Frank,

I am sorry i came across as being "smart" but the answer i was looking for was in your second post.
If we start at 0-2 degrees and work toward 34, then dip back slightly before full throttle we'll match Chryslers curve.

You are obviously far more knowledgeable that i am when it comes to this boat stuff. We did check compression, they are all within 5 pounds of each other. The stock CDI is cooked so we cant run it before we install our C5 system.

May i ask, are most two stroke outboards designed with an extremely linear curve? It's odd to me that the timing would not be extremely retarded on the top end. Our plan is to plot a curve that gets it running, then we can tune as needed once i know the engine rpm on the boat we have. You bring up great points about prop pitch...its not so cut and dried on boats as it would be on a motorcycle!!

If you have time, check out C5 TECHNOLOGY - C5 Performance to see what i mean about the timing curves. We have to tell the computer what timing to start and end at before we download into the ignition.

Thank you again for your help. If you have more interest in this stuff let me know. I'll post on here when we get it running. Wish us luck!

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Newer outboards, both two and four cycle are finally computer controlled with fuel injection--getting away from 50 year old technology. Right now I have very little experience with them but suspect that they do modify timing: On a Suzuki 30 that I rebuilt, there are two flywheel sensors that tell the computer what RPM the flywheel is turning and rate of change. The computer adjusts the timing advance and I am sure the engineers had something to say about this.

Older 2 cycle outboards almost universally have linear advance--probably because: 1. It is/was cheaper to manufacture and 2. It worked well for the running parameters the outboards used: Start, put in gear, and either cruise at one speed or run at full throttle. With this limited RPM use range, esoteric timing was simply not needed.

Now, on your Chrysler, the head and piston design is probably about 60 years old. They did know about certain design principles (like hemispherical chambers with squish bands) but did not use them. The engine is a dirt simple straight crossflow design with a very large baffle on the piston crown to deflect gases. The head is shaped to the piston and "packed" a bit so as to get adequate compression. However, gas turbulence and flame front speed were really not considered. That is why such a big advance timing at wide open throttle is needed. (remember: For maximum power to be developed, there must be a equal burn time before and after TDC.)

The pistons are very heavy and the connecting rods are short, and timing advance is almost double that of a loop charged engine, leading to less power than a differently designed engine of the same displacement. Burn time in your Chrysler is about 60 degrees while burn time in a loop charged engine is about 30-40 degrees. SO: peak and average pressure is less and horsepower is less. You can't fight physics.

All this is an explanation: While you may make some modest gains with timing, such gains may very likely not be noticeable as an increased top speed. Remember: It takes four times the power to double speed and on my test hull, a 35 horsepower increase from 90 to 125 only yields 5 MPH.Similarly, because there is so little turbulence, an MSD ignition MAY or MAY NOT yield increases. The multiple sparks would be firing in already burned gases. On the other hand, they may help prevent misfiring.

You simply can not make a silk purse out of a sow's ear. However, If you can squeak out an extra 10-15 horsepower on a 94 cubic inch displacement engine (only about 60 effective with port area taken into consideration) with timing you may have something.

 

[C5Paul]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Newer outboards, both two and four cycle are finally computer controlled with fuel injection--getting away from 50 year old technology. Right now I have very little experience with them but suspect that they do modify timing: On a Suzuki 30 that I rebuilt, there are two flywheel sensors that tell the computer what RPM the flywheel is turning and rate of change. The computer adjusts the timing advance and I am sure the engineers had something to say about this.

Older 2 cycle outboards almost universally have linear advance--probably because: 1. It is/was cheaper to manufacture and 2. It worked well for the running parameters the outboards used: Start, put in gear, and either cruise at one speed or run at full throttle. With this limited RPM use range, esoteric timing was simply not needed.

Now, on your Chrysler, the head and piston design is probably about 60 years old. They did know about certain design principles (like hemispherical chambers with squish bands) but did not use them. The engine is a dirt simple straight crossflow design with a very large baffle on the piston crown to deflect gases. The head is shaped to the piston and "packed" a bit so as to get adequate compression. However, gas turbulence and flame front speed were really not considered. That is why such a big advance timing at wide open throttle is needed. (remember: For maximum power to be developed, there must be a equal burn time before and after TDC.)

The pistons are very heavy and the connecting rods are short, and timing advance is almost double that of a loop charged engine, leading to less power than a differently designed engine of the same displacement. Burn time in your Chrysler is about 60 degrees while burn time in a loop charged engine is about 30-40 degrees. SO: peak and average pressure is less and horsepower is less. You can't fight physics.

All this is an explanation: While you may make some modest gains with timing, such gains may very likely not be noticeable as an increased top speed. Remember: It takes four times the power to double speed and on my test hull, a 35 horsepower increase from 90 to 125 only yields 5 MPH.Similarly, because there is so little turbulence, an MSD ignition MAY or MAY NOT yield increases. The multiple sparks would be firing in already burned gases. On the other hand, they may help prevent misfiring.

You simply can not make a silk purse out of a sow's ear. However, If you can squeak out an extra 10-15 horsepower on a 94 cubic inch displacement engine (only about 60 effective with port area taken into consideration) with timing you may have something.

Frank,

Great news! We got this beast running using a wasted spark 4 stroke program. I made a curve prior to getting your information so we had it all wrong, but the engine runs.
We started at 10 degrees and went to 11, then tapered back to 10. This was just to get it fired up, and before you helped us with this, we didnt know how far advanced we could go.

So this weekend we are going to put a timing degree wheel on the flywheel and set it to 30 degrees at full throttle. Then as we roll off the throttle we'll record what the timing does until we get to idle. I will share this with you when done. I have a 4 day trip coming up so i'll post after i get home.

Our next step will be to run it on the lake and see how it reacts to more and less advance. It will be a valuable lesson for us. Thank you again for your help...we appreciate it!

 

[Frank Acampora]

Re: 1978 chrysler 105hp ignition problem (restoration project)

Just don't go past 30 ( or with good gas 32) degrees. At 40 degrees advance she will melt holes in the pistons---DON'T ASK HOW I KNOW! LOL Older Chryslers were originally timed at 32 degrees advance at WOT. Then, around 1980 the factory reduced specifications to 30 degrees citing poor quality marina gas. Unless you are all out racing and need every fraction of available horsepower, you can't go wrong with 30 degrees.

Wasted spark? I think some older OMC V4 engines did use this too.