73 85hp rude Head scratcher

[tashasdaddy]

Re: 73 85hp rude Head scratcher

looking at the weather, no time to be at work. need to stay home and batten down the fort. good excuse anyway.

 

[wavrider]

Re: 73 85hp rude Head scratcher

Well I made it to work, at the shop not the office.

Timer base ohmed at 12 ohms. replaced it with a good base ohmed 8.5 on the money.

cleaned, carb bottom one, used that high dollar napa carb cleaner, it is good stuff, better last the next 3 years for the price.

Results.

I have a 7/16 spark on all 4 cylinders, checked with all spark plugs in and using a spark tester, measured to 7/16. The spark is not blue, it is yellow on # 4, blue on #2, blue on #1 and yellow on #3.

I can take the plug wire off while engine is runing and no difference on #4, pull the plug wire off on #2 and the engine stalls and dies. Pull the wire off of #3 and only a slight difference. Pull the wire off of #1 and it barely runs.

I can put my fingers into the throat of the bottom carb and it makes no difference in the way it runs. I put my fingers in the throat of the top carb and it chokes the engine out and dies. fuel is flowing great into the bottom carb as my fingers come out all wet when I put them in the throat and of course can feel it being drawn into the intake, reeds looked good as far as I can tell, can not see the bottom reeds due to angle.

I guess I could swap sensoe #1 and #3 h and swap sensor #2 and #4 to see if I now get blue spark on #3 and #4.

I had a bad timer base high ohm cause weak spark, now it look like one side of my powerpack is weak also?? Only running on top two cylinders?

I can hear it increase in rpm and then decrease, intermittently, sure sounds like ignition.

stator is good or there would be no spark at all.

Is it time for a new powerpack and coils or just order powerpack?

Waiting for replies before starting to throw parts atthis old rude.

thanks for all the help

 

[wavrider]

Re: 73 85hp rude Head scratcher

Weather gave a break and went back out to the rude.

The donor engines donated a powerpack.
got great blue spark 7/16 and beyond.

Changed the timer base with one that ohmed correct, changed stator while I was at it had a newer green one.Changed powerpack. Cleaned carbs. Link n sync. New plugs gapped at 030

Runs like a champ in the tank, no hesitation, no revving up of rpm. smoth acceleration.

Things learned.

Timing lights lie. Have to check with the spark tester.

Circuits will produce spark but not enough to fire a cylinder under compression.

Insulated pliers are not really insulated after a rain and the ground is soaking wet.( that one stood the hairs on end and sent the pliers flying across the yard, goats thought I was crazy)

This forum is full of great, knowledgeable, helpful members.

If not for JayMerrill driving home the ignition could be the culprit I would have tore into the intake of the 85hp. Big thanks to Jay and all the rest of the members who donated their time and knowledge to assist me in this project

 

[HighTrim]

Re: 73 85hp rude Head scratcher

Glad you got her, figured it was the isolation diodes. Now really take a day off and go fishing

 

[wavrider]

Re: 73 85hp rude Head scratcher

I wish I could. really should not have taken today off but I knew if I went into the office that all I would think about was that problem with the rude.

So wat the heck stay home n fix it. Thanks again all.

 

[patrick4266]

Re: 73 85hp rude Head scratcher

glad you got it fixed again. I wish I could work on mine. it was 78 sunday. 10 inches of snow today but thats st louis for you.

 

[jay_merrill]

Re: 73 85hp rude Head scratcher

Glad that you got the problem sorted out and I learned something too - the correct ohms reading for your sensors (8.5 ohms) is the same as for my 1972 Johnson 65hp, not the 38 - 42 ohms suggested by the link that I provided. I am also not surprised at the reading that you got when testing the your sensors because I just went through all of this with my motor and got exactly the same reading on the sensor that turned out to be bad - 12 ohms.

Now, go "kill" some fish!

 

[wavrider]

Re: 73 85hp rude Head scratcher

Saturday afternoon is fish hunting season. wonder if the fishfinder will work at 40+ MPH

 

[wavrider]

Re: 73 85hp rude Head scratcher

Tested on the lake today.

Started up ok, cold weather here today in the 50's

Good hole shot, got on plane great, 5500 wot at 32mph, lost 5 mph on top end,I did some adjusting on the engine raised it to high I think so will reset that later. At least the tach shows I am hopefully hitting on all 4 cylinders as before could only get 4000 rpm but engine was set lower then.

Half way across the lake bogged down, stalled. Immediately restarted and off again. started bogging agai pumped the primer bulb and off again. weak fuel pump. ran for 15 mins at 4000 rpm but go to WOT and it bogs, so will order new fuel pump.

After running a while went back down to idel in gear, still had intermittent miss. got to be a weak coils, going to go ohm the coils now and see which one is out of tolerance. If I cant find a weak one I will order four new ones and be done with it, hopefully. thanks for all the help and advice.

 

[wavrider]

Re: 73 85hp rude Head scratcher

Not coils,

Good blue spark, but not always, sems like when it does spark it has a good spark, but it is intermitent like the switching diodes are only working sometimes.

spark good for a few revolutions then no spark for a few revolutions then back to spark again.

spark plugs out and good hot battery so engine was turning plenty fast enough to produce spark, timer pickup coils still ohm 8.5 on the money.

ordering new powerpack and 4 coils, fuel pump. should not be any problems after that.

 

[tashasdaddy]

Re: 73 85hp rude Head scratcher

make sure your tank vent is clear, my 88 spl did the same thing about slowing down, dirt dobber in vent, was not completely clogged, but restricted the flow at wot.

 

[wavrider]

Re: 73 85hp rude Head scratcher

I hope it was clear, just filled the tank yesterday, took a loan out for that, price of gas is going crazy.

I lied cant find the fuel pump on iboats for this engine, Ishopmarine must think there pumps are made of gold

brp part number 438559, can not find cross reference to sierra any ideas??

 

[ezeke]

Re: 73 85hp rude Head scratcher

How about:
http://cgi.ebay.com/ebaymotors/John...008QQitemZ180220815316QQrdZ1QQsspagenameZWD1V

Product Details: Part Number:0385784Description:FUEL PUMP AY Pack Qty:1Dimensions:3.50 x 3.50 x 2.25 (in)Weight:0.44 lbsEquivalent Parts:0395712,0398385,0433390,0438559

 

[wavrider]

Re: 73 85hp rude Head scratcher

How about, Done deal.
thanks Ezeke should have it this week hopefully.

 

[wavrider]

Re: 73 85hp rude Head scratcher

Recieved the fuel pump today, no time install still trouble shooting the ignition.

Great voltage from stator to brown, brown yellow over 150,, sensors all good voltage above 150

output to coils all above 150 measured with home brew dva adapter, should have factory made dva adapter in next week, time in shipping ughhh

ohmed out all the coils in accordance with recomendations, coils do show meter deflection.

installed new amp today recieved it in 3 dys fast shipping, still waiting on the other amp and 4 coils i ordered.

Still weak spark on 3 cylinders, has to be coils, only thing left not replaced in the ignition, well 2 were replaced with coils that did ohm out correct but not with new ones.

I am getting 2K ohm of rsistance between the spark plug boot n ground and to the input orange wire.

I read another post that someone else ohmed thee coil and got 240 or 245 ohms on the coil.

does anyone know what a known good coil should ohm out at?
spark plug boot to ground??
spark plug boot to input orange wire from amp?

thanks for the replies, about to get this thing whipped i think