Johnson Wont Plane Boat

[roofcock]

i have a 17 foot monark bass boat with an 85 hp johnson (1976 model) the engine starts fine and revs up fine. the problem is when i push the throttle down the motor does not rev up past (i am guessing- no tach yet) 2500 or 3000 and the boat wont plane or do over about 20 or 25 mph (no speedo). i also have a 15 ft bass boat that with the same motor and prop it would push it about 43 - 45 mph and would get on plane quick. same motor meaning a 76' 85 hp johnson. my 15 footer rotted and i bought this 17 to get on the water. i now have three running 85hp outboards but have not tried the other two. both boats have a tri hull design. using a 13 1/4 x17 prop and the concept of 200 rpms per pitch would mean i need a negative prop to move this boat. any ideas on the problem, thoughts on what to check or otherwise would be appreciated. i currently have a 76' 85 hp javelin a 76' 85 hp sea horse and a 78' 85 hp sea horse. short of changing motors i am at a loss. any advice appreciated, thanks in advance

 

[1730V]

Re: Johnson Wont Plane Boat

Are you sure the hull is not waterlogged?

Do a compression test on the engine and let us know.

 

[roofcock]

Re: Johnson Wont Plane Boat

i got the boat from a guy a short time ago and am toying with it till i have to winterize it. rear is dry i am not sure it is not water logged in the front i would not know. but it wont plane so if the front was full wouldnt it sit down in the front and help it plane. i will try a compression test tommorrow. if it is low the guy that listed it on ebay will have a bad name here. i did not buy it from ebay but someone did
the following are the boat and motor before i got it, and after i got it. the guy i got it from was not well versed in boats. long story short he had more dollars than sense, wanted to get on the water, realized he should buy new, then did, and you could say i made out for what i paid, if i can make it plane.
(#220135354907) THIS IS THE ITEM NUMBER OF THE MOTOR BUT CAN NOT ATTACH URL
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=220135354907
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230157360362
http://cgi.ebay.com/ebaymotors/ws/e...=ADME:X:RTQ:US:11&viewitem=&item=120162235103

 

[1730V]

Re: Johnson Wont Plane Boat

I also suggest you work with the guy you bought from before flaming anyone here.

Are you sure your controls are working correctly and adjusted correctly? Are the throttle (Butterflies) opening up all the way? Is the timing arm advancing all the way?

Revving in nuetral tells you nothing. Not only is not a good idea, it can destroy the engine quickly.

Without a working tach. a lot of this is guess.

 

[tashasdaddy]

Re: Johnson Wont Plane Boat

i suggest checking compression and spark, before anything. and post your results.

 

[roofcock]

Re: Johnson Wont Plane Boat

i am going to hook up a tach and check all i know of today. as far as flaming anyone ,i would not, simply because i did not purchase it from him directly. but if you see what the other guy paid for it and it proves to be a mechanical issue you would see where it came from only to be fore warned before anyone else purchases from same seller. however, i spoke to this guy and he seems to be a decent guy so no i wont be flaming him.

 

[tashasdaddy]

Re: Johnson Wont Plane Boat

check spark and compression, lets you know if you have a viable base to work with. then go from there.

 

[roofcock]

Re: Johnson Wont Plane Boat

i checked the spark, only firing on two cylinders then one cylinder. it was late in the eveing and i was alone so i waited for assistance with the key switch. so i tried the next eveing and confirmed two cylinders firing. next day i get home early and have the oportunity to mess with it. i check the compression for giggles and farts and all is well. (115 - 125 between them all) so i cant remember which ones fired and do spark check again. imagine that all four have fire. don't get it. again i was needing some giggles and farts so i hooked up the hose and rabbit ears to start the motor. started motor and pulled plug wires one by one to see if it made a difference. three of the four made a large difference. i then checked the spark again. what happen? fire from only one cylinder. so i pull out the ohm meter and do the tests i can with that. i do not have the neon tester. i know two coils are new and the power pack as well. has any one had this happen to them who may have an idea. thank you for you time

 

[CharlieB]

Re: Johnson Wont Plane Boat

Swap coils side to side, retest.

Swap ign modules, retest.

What were the results, did the spark or lack of spark change sides?

Try using a remote starter button (don't need a helper to turn the key) disconnect the throttle cable and move the throttle/timing advance, move trigger wires, does spark come and go from a broken wire?

Try to rule OUT coils, modules and trigger.

Beg, borrow or buy a DVA meter and test stator and triggers and modules output to coils.

Dva meter and remote starter button are my BEST tools for troubleshooting ignitions, along with my spark tester, that's a GOTTO have.

 

[roofcock]

Re: Johnson Wont Plane Boat

THE SPARK CHANGED LOCATIONS MAnY TIMES. sometimes lower right cyl. upper left.. it would vary side to side

 

[HighTrim]

Re: Johnson Wont Plane Boat

NO SPARK OR INTERMITTENT ON ONE OR MORE CYLINDERS:

Check the DVA output on the orange wires from the power pack while connected to the ignition coils. You should have a reading of at least 150V or more. If the reading is low on one cylinder, disconnect the orange wire from the ignition coil for that cylinder and reconnect it to a load resistor. Retest. If the reading is good, the ignition coil is likely bad. A continued low reading indicates a bad power pack.

NO SPARK OR INTERMITTENT ON ONE BANK:

1. Check the timer base’s resistance from the #1 to the #3 sensor wire, and from the #2 to the #4 sensor wire. Reading should be 10-20 ohms on each set (or 30-40 ohms for CDI Electronics Blue Timer Bases).
2. Check the DVA output from the timer base. A reading of at least 0.5V or more from the #1 to the #3 sensor wire, and from the #2 to the #4 sensor wire (while connected to the pack) is needed to have spark. If the output is low, you may try to reset the air gap between the timer base sensor and the triggering magnet using a sensor gap gauge or use the procedure outlined in the previous page.
3. Check the DVA output on the orange wires from the power pack while connected to the ignition coils. You should have a reading of at least 150V or more. If the reading is low on one cylinder, disconnect the orange wire from the ignition coil for that cylinder and connect a load resistor to that terminal. Retest. If the reading is now good, the ignition coil is likely bad. A continued low reading indicates a bad power pack.