1989 mercruser 370/165 hp starting question

had this boat for 6 or 7 years now, so a little history
replaced alternator with an external kit ( 5 years ago),
engine water pump and seal and the cam slieve) and head gasket done carb replacement and rebuild (4 years ago),,
pertronix ignition and dist rebush (3 years ago),
out drive water pump, lower shift cable and drive shaft support bearing last year
So the issue i have is starting, i have to and expect to set the choke with the throttle and pump the throttle at least 3 times ( adds fuel with the accelerator pump)to get the engine to start cold, usual cranks about 15 seconds and fires up. it idles and runs well through out the entire rev range does not stumble or backfire. BUT when hot i have to pump the throttle 5 to 6 times and hold the lever almost fully opened to get it to start after about 20 seconds cranking, after start it idles normally ( about 700rpm) and runs fine.

so how do i cure the starting issues , any help would be much appreciated

thanks
chris

Next time, try only moving the throttle (push center button in as normal for throttle only use) to about 10:00 to 9:00 position only. Do not pump.

thats it........

chrisfiat said:

pertronix ignition and dist rebush (3 years ago),

So the issue i have is starting, i have to and expect to set the choke with the throttle and pump the throttle at least 3 times ( adds fuel with the accelerator pump)to get the engine to start cold, usual cranks about 15 seconds and fires up. it idles and runs well through out the entire rev range does not stumble or backfire. BUT when hot i have to pump the throttle 5 to 6 times and hold the lever almost fully opened to get it to start after about 20 seconds cranking, after start it idles normally ( about 700rpm) and runs fine.

so how do i cure the starting issues , any help would be much appreciated

thanks

Click to expand...

chris, over the long term (if this is not corrected), you will eventually shorten the life of your starter motor. Also, long cranking certainly doesn't help battery life.

As you likely know.... today's auto and Marine fuel injection systems automatically enrich fuel/air ratio for cold-starts..... so we don't even give this a thought.
On the older carbureted models, the choke and accellerator pump action creates fuel enrichment for cold starting.

With a warm engine, we should not be required to use any accellerator pump action, nor any choke enrichment.

I agree with kghost..... during warm engine start up..... move the throttle lever forward, and try to NOT actuate the accellerator pump any more than once during the throttle position change.



Since this engine used a kettering system (contact points) as OEM, your ignition system may incorporate a "start-by-pass" circuit.
If so, you may want to try disconnecting the ignition coil lead from the ballast resistor, and allow the coil to recieve power from the "start-by-pass" circuit only.
See if the engine will fire up during cranking ONLY. In other words... while the starter motor is engaged.
If so.... then the "start-by-pass" circuit is working.

If not... then perhaps the "start-by-pass" circuit is not working.

IOW... it may be an ignition issue... not necessarily fuel related.

I do not care for the Pertronix kits, but these are an affordable alternative for this engine.
Worse case... re-install the contact points and condensor. Set the dwell using a dwell meter... not by gap only..... and give it a try.


It's pretty tough for any of us to help you diagnose this via the keyboard only.



.

Since this engine used a kettering system (contact points) as OEM, your ignition system may incorporate a "start-by-pass" circuit.
If so, you may want to try disconnecting the ignition coil lead from the ballast resistor, and allow the coil to recieve power from the "start-by-pass" circuit only.
See if the engine will fire up during cranking ONLY. In other words... while the starter motor is engaged.
If so.... then the "start-by-pass" circuit is working.

If not... then perhaps the "start-by-pass" circuit is not working.

IOW... it may be an ignition issue... not necessarily fuel related.

I do not care for the Pertronix kits, but these are an affordable alternative for this engine.
Worse case... re-install the contact points and condensor. Set the dwell using a dwell meter... not by gap only..... and give it a try.


It's pretty tough for any of us to help you diagnose this via the keyboard only.

.[/QUOTE]

A properly installed pertronix system will not incorporate he resistive wire that that goes to the coil on these engines, making the starter bypass power to the coil redundant. this system is wires to give the ign sys full 12 volts all the time. And ye i agree that prolonged cranking will ruin the starter eventually. As to the fuel yes it should start with out the accelerator pump priming the engine but it will not.

As to the issue of Pertornix systems, i have used them for over 30 years in the automotive business we install multiple units every year in our customers older antique mg, fiats triumphs vw, so i have a lot of experience with them, and they are top notch units for the money. just wire them up correctional

thanks for your replay

kghost said:

Next time, try only moving the throttle (push center button in as normal for throttle only use) to about 10:00 to 9:00 position only. Do not pump.

thats it........

Click to expand...

Chris, try this^^^^^^^^^ After the engine is warmed up. Really sounds your flooding the engine, then unflooding. Good chance she will start much more quikly. Rick

........................

chrisfiat said:

A properly installed pertronix system will not incorporate he resistive wire that that goes to the coil on these engines,
Key word "Properly".
Do we know that the Pertronix unit was installed and wired correctly?

making the starter bypass power to the coil redundant.
Redundancy was not the original concern.
The original issue was that battery voltage could be down around 10.5 or 11 volts while cranking.

As to both of my above comments.... keep in mind that this engine was previously fitted with a contact point ignition system.
Please let us know how the contact point system was abandoned, and how the Pertronix system was installed.
This will remove any guess work on our behalf.

this system is wires to give the ign sys full 12 volts all the time.
Incorrect!
Battery voltage can be down around 10.5 or 11 volts while cranking.


And ye i agree that prolonged cranking will ruin the starter eventually.
Agreed.


As to the issue of Pertornix systems, i have used them for over 30 years in the automotive business we install multiple units every year in our customers older antique mg, fiats triumphs vw, so i have a lot of experience with them, and they are top notch units for the money.
Pertronix themselves have anounced that their Hall Effect units have shown errors of up to 1.5 degrees.
This was brought to our attention several years ago by one of the MarineEngines.com forum members.

Click to expand...

The Pertronix kits use Hall Effect triggering.
There is nothing wrong with Hall Effect intrinsically, except with how this company does it..... IMO!
The triggering magnets are embedded within a molded plastic ring. Not only a molded plastic ring, but a ring of a small diameter.
As we all know, more precision is required within a small diameter than would be a larger diameter.
Hall Effect is widely used, and it is a good system....... but we will rarely see it used in a diameter such as what these kits use.

There is only one engine that I'll use this kit in.



.

ricardo of course it was installed correctly, i did it myself, and followed the directions, which i am intimately familiar with, as i said i have been using these units for 30 years.
and yeh we know all about the need for higher voltage during cranking that is why the ign coil has the resistance wire bypassed during cranking. as i said this system has been bypassed as necessary for the pertronix, and of course cranking voltage will be lower, that is why the resistance wire was bypassed to give the engine some hope of starting.

now I am surprised you didn't know that my problem is.............. i will give you a hint, it is called voltage drop, and NO it has nothing to do with the ignition system in this case.

Chris, lets reconstruct this and see what it is that's bothering you.

In post #1, you offered us a bit of history about the boat, including several things that had been done and items that had been replaced. You then state the problem that you're having while starting this engine, and close with; "so how do i cure the starting issues , any help would be much appreciated."

Nothing in post #1 mentions your experience or qualifications.
Then Kghost, fastatv and I chimed in with some suggestions for you.

Then I get this rather chastizing response from you:
(no offense taken, by the way!)

chrisfiat said:

ricardo of course it was installed correctly, i did it myself, and followed the directions, which i am intimately familiar with, as i said i have been using these units for 30 years.
This was not mentioned previously.... so how would we have known this?

and yeh we know all about the need for higher voltage during cranking that is why the ign coil has the resistance wire bypassed during cranking.
Yes.... and is why I also eluded to that.

as i said this system has been bypassed as necessary for the pertronix, and of course cranking voltage will be lower, that is why the resistance wire was bypassed to give the engine some hope of starting.
Again, I don't recall this being mentioned previously.... so how would we have known this?


now I am surprised you didn't know that my problem is.............. i will give you a hint, it is called voltage drop,
If you suspect that this is your issue, then it would appear that you had your answer from the beginning... yes/no?

and NO it has nothing to do with the ignition system in this case.
Again, if you suspect this.... then perhaps you know what the issue is!

Click to expand...

Look, all that we can do is read the OP's first post in his/her thread, and hope that it's been complete and informative.
Then we take a stab by offering our suggestions to the OP.

If the OP has given us enough clear and complete details, we can usually be of help.
However, if the OP has not offered enough info, or has held back info until furter into the thread, we can't be quite as helpful.... yes/no?


Chris, please consider the above and understand that there's no need to get into a tizzy over any of this. We are trying to help you.
So help us help you... and perhaps we'll get somewhere with your issue.
Fair enough?




.

No ricardo i didn't know what the issue was from the beginning other wise i never would have posted the question.
Further testing reveals the issue to be a voltage drop problem, causing a lower than sufficient cranking speed, seems the b+ cable to the starter had .9v drop, cable cleaned and terminal replaced, and a fully charged battery and thing spins over like never before, starts hot or cold as it is supposed to, and the suggestion that i may have been flooding then clearing out by the long hot crank seems to have been right on as well, moving the throttle to about the 10:00 position works great.

chrisfiat said:

No ricardo i didn't know what the issue was from the beginning other wise i never would have posted the question.
Further testing reveals the issue to be a voltage drop problem, causing a lower than sufficient cranking speed,
1..... seems the b+ cable to the starter had .9v drop,

cable cleaned and terminal replaced, and a fully charged battery and thing spins over like never before, starts hot or cold as it is supposed to, and the suggestion that i may have been flooding then clearing out by the long hot crank seems to have been right on as well, moving the throttle to about the 10:00 position works great.

Click to expand...

1... Perhaps I misunderstood you... but if your B+ cable runs directly to your stater motor, you may not have an MBSS (main battery selector switch) in your battery system. These are a necessity, IMO.


If you do have an MBSS, the older Perko MBSS in the 90* sweep version, have very light contacts and a very light tension spring. These can be problematic and can cause a voltage drop during heavy cranking loads. This can be an even greater issue if your starter motor is not a HTGR/PMGR unit.

BTW..... Excellent trouble-shooting!
I'm glad that you got this sorted out!


.

just one battery on this boat

chrisfiat said:

just one battery on this boat

Click to expand...

Honest questions:

• if no MBSS or BS (battery switch), where is your ability to shut down the 12 vdc system when the boat is un-attended?
• how is this achieved on a routine basis?
• if only one battery, where is your redundancy?

Just curious!


.

RicardoMarine said:

Honest questions:

• if no MBSS or BS (battery switch), where is your ability to shut down the 12 vdc system when the boat is un-attended?
• how is this achieved on a routine basis?
• if only one battery, where is your redundancy?

Just curious!


.

Click to expand...

the answer to all your questions is the same
i remove the key, and have the same level of redundancy as your car