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1986 Johnson GT 150HP Trouble

wtp

Member
Been reading these forums for a few days and got some mixed feelings on some of my problems. I have a 1986 GT150 on a hydra sport. When I bought the boat of coarse the guy said it ran good. Well finally got it out and couldn't got more than 24 mph out of it and every time you stop you have to reprime and hurry up and restart it before it loses prime. Long story short got it home and found cracked gas lines. Replaced all lines and primer ball. Checked pickup tube and was fine. opened carbs up and blew through all jets with compressed air. Took it out again and samething. nothing more than 24mph not sure on rpms tac don't work. got it home and checked compression. 91-92-91 on starter side the other side had 100-99-100 from what I read it's with in specs. Put new plugs in since had them out. Took carbs off again looked a little closer at them but seem fine. not sure if it makes a difference or not but I'm preety sure I got them right but might have carb 1 and 3 switched around. Don't think so though. Now looked at fuel pump (VRO was compltely removed by somebody else) diaphram was questionable. possiable leakes by screw holes. and some of the plastic seems to be cracked. took my fuel pump off my 50hp force that I know was good. took it out again and now your lucky to go 5 to 10mph and thats if i keep reaching back and priming the bulb. I could be wrong but I thought any vacuum ran pump would work. I guess I was wrong. Any ideas what I can try or do.

New fuel lines
new primer ball
checked pickup tube in tank - was fine
checked compression - good
new plugs
no VRO pump
diffrent fuel pump - pump good off force 50hp
carbs are clean - seem to be
batteries are new
charging system working 14v while driving

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Any help would be great
 
i was told that it would not run real good at idle if it were the reed valves. not sure if thats true or not but it seems to run good at idle and at slow speeds just not at high speeds. as far as the high speed jets, I didn't take them out of the bowl but blew 120psi air through them and air came out the otherside.
 
been doing some reading and found many places that I need to run 2 fuel pumps but can't find a a 2nd spot for the pulse signal on the crank case. any ideas
 
I made a spark tester and I found I don't have a steady spark. It will hit a bunch of times then theres nothing and then it hits again. with all plugs out it looks to be a white spark. I'm not seeing the blue eveybody talks about. The missing spark happens on both middle cynlinders the most. I set it so the spark will jump 1/2inch.
 
How are the flywheel magnets ???--------------Time to run the tests on charge coils , sensor coils.-----------------Possibly mark the flywheel to check timing of each cylinder.--------Flywheel key checked ??
 
How are the flywheel magnets ???--------------Time to run the tests on charge coils , sensor coils.-----------------Possibly mark the flywheel to check timing of each cylinder.--------Flywheel key checked ??
I'm gonna pull flywheel off tonight to take a closer look. I have checked WOT timing but how do I check timimg for each cylinder?
 
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Still having problems with my boat. I took the coils off and had them tested and they tested good. Replaced the wires because the old ones had alittle rust in them. When I had the boat out tonight I noticed some I think mixed gas seepage by where I think the crankcase seperates but I'm wondering if it aint coming out of them little covers on the side of the head. Either way I wouldn't think there should be gas in either location. The red line is where the gas is running down. It's not alot but it is noticeable. The other pic is where the coils are and seem to be somekinda oil but doesn't seem recent. Not sure if it is part of my problems but It is something I noticed. tonight I built a spark tester. now from what I read the spark should jump 7/16 inch. I set it at 1/2 inch and all do jump. Here is my concern It's not a "wide" blue spark like I read. It is more of a thin whiteish spark and it's not a constant spark. You'll get like 5 or 6 in a row and the a pause, then 3 and then a pause. numbers are not exact but you get the idea. not a constant spark. i did do the test with all plugs out. and yes the tester was plugged right into the coil. not sure if it maters but my tester plug wire is about 16 or 18 inches long and ground wire is about the same. Any help would be great.
 
There sure is gas and oil going thru the crankcase , so those leaks could indicate a problem.---------------------Has this motor been apart lately and by a shop ????
 
It should not leak crankcase compression at the joint !!---------You may want to replace the gaskets on the 6 covers and see if that cures it.
 
I'll have to see what happens. All my parts showed up today. I got new reed valves but found out there good. See very little light on a few but according to the book you will but as long as it's no more than 0.010 on the feeler gauge. I'm well smaller than that. I did put new gaskets in though. Also replaced the big intake gasket. I also picked up a new stater cause mine was black (burnt) on the 2 thing were the wires come out. It still charged though. Picked up new power packs also and the 6 cover gaskets and will get them in today. I also picked up a new rectifier but mine looks brand new. There isn't even dirt or anything on the wires or the box. I know that doesn't mean anything. I'll try figure out how to test that later today or tomorrow. My goal is to dump it into the lake this weekend and give it a shot.
 
Here's a shot in the dark...don't laugh. I once had a 1996 175 Ocean Runner that did the same thing you are describing. It ended up being a clogged screen in the fuel line that's in my main tank. It looked like a small piece of white rubber that was restricting my fuel.

Just a shot in the dark.
 
everything for fuel are new. From the pickup tube in the tank to filters, pumps, lines and carb kits. does anybody know if there is a certain order the carbs go back on. The middle one is easy do to the throttle linkage but does it matter for carb 1 & 3? I have them soaking in carb solutuion now and would like to clean them and reinstall tonight. Also i wrote down where my yellow stater wires go with one yellow and one yellow with a gray strip but got my new stater and there is no markings just 2 solid yellow wires.
 
well still no go. I put in those 6 gaskets (3 on each side of block) put new power packs on, soaked carbs in berryman cleaner. Found nothing in the jets. Checked jets and they are the right ones for the carbs. rechecked fuel lines. put on a tach. had a buddy drive next to me with a 85 force we were going 35mph and tach was reading 4900 rpms. my speedo says 25mph so that don't work right either. top end is smooth but should be faster. this is the best part. choke the hell out of it and it starts to spit and sputter then you have to grab the fast idle and rev it up to clear it out. it sputters until it gets going and then smooths out. carbs seem dry but on start up it's all wet like there flooding. But have to use choke to start it. Not sure if it's getting gas running out the front of the carbs from flooding or from it sputtering which still could be flooding. I'm total lost now. Here is a summry of whats been done. New plugs, wires, fuel lines, 2 fuel pumps, power packs, stater, 6 side gaskets on the side of the block, reeds are good, replaced intake gaskets, set timing (used directions in top secret file section) cleaned carbs 4 times, jets are clear, float is level when held upside down, new needle and seat. checked pickup tube in tank. shot gas in carbs with spry bottle at wot and motor seem to bog down when I did it but that was a hard test trying to drive the boat and spray gas. also new prime bulb and checked compression which was within specs. So there it is. Whats next other than let it sink.
 
UPDATE:

I still have not got this motor to run right. To many things are not adding up. One day runs "ok" next time trolling motor has more power. 2wks ago i decided screw it, it wasn't working the way it was so I tore it down. Pistons, cyclinders and crank all look good. Bought OEM powerhead gasket kit, 2nd set of needle n seats (OEM this time) and new mid and high speed jets for the carbs and new fuel check valves. Got it back together and it did run but leaked alot of water right below the power head. I did put a new gasket in there but looks like it might be just a little lower than that. I'll hopefully know more today (8-13-11) cause I'm pulling the power head off again to see if maybe the gasket is ripped or something. Will post results. Oh and this motor has been ripped apart once before. There was 2 newer pistons in it. did kinda look like there was poor sealer between crank halfs. looked alittle thin in areas and possiable traces of leaks. I started another thread and a nice gentleman is gonna try get me a pic of his check valve hose connections. I'm not 100% I got mine right.​
 
Well for one thing the sealer is----------SUPPOSED TO BE THIN----------on proper assembly it is a metal to metal joint !!-----------99 % of the sealer should squeeze out.-----------If sealer is too thick than bearings will not be seated properly .----------What did the crank seal rings look like ???----What did the lower crankshaft seal look like ??------------------Magnets on the flywheel checked for looseness.--------------------Put a timing light on each cylinder and see if you have spark on all six.-----------------Put 6 timing marks on the flywheel and see if each cylinder fires properly.
 
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Went through your post and have some comments.
from the pics:
1 Plug wires. They do not look original. Anything but 'solid core' wires may ruin the ignition system and reduce your spark.
2: Your pee-hose should be routed over the top of the cylinder and down. Be sure to use the original nipple in the lower cover, or at least something with the same flow/hole.
Then I do not see a max timing performed after rebuild?
You need to get your rpm's verified and info about your prop as well is missing. Perhaps a pick from the rear showing installation hight?
Any history about the boat and previous engines and speeds?
If a hook at the bottom, it will 'suck' and stop at certain speed no matter how much power you put on it.
Perhaps the main problem is not the engine but the boat itself?
 
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Went through your post and have some comments.
from the pics:
1 Plug wires - Accel performance wires.
2: Your pee-hose should be routed over the top of the cylinder and down - Doing that tonight
3. Then I do not see a max timing performed after rebuild?
Set that to 28 degrees. Motor cover says 24 degrees / 28 max spark advance timing. which one should it be?
4. You need to get your rpm's verified - Now after I raised the motor 1 hole I'm running 5200rpm at 35mph.
5. info about your prop. 15x17 is what it says
6: Perhaps a pick from the rear showing installation hight? cavitaition plate is 1" above lowest point of bottom of boat
7. Any history about the boat and previous engines and speeds? ran "ok" 24mph at 38 to 4000rpm
8. If a hook at the bottom, it will 'suck' and stop at certain speed no matter how much power you put on it. Not sure what your saying here?
9. Perhaps the main problem is not the engine but the boat itself? Could be, I have a pic of the boat when I first got it before I did anything to it. I'll try post it.

The boat did run pretty good yesterday. It will not time on idle. If I try get to 6 degrees it sputters and wants to die. Yes went throuh the carbs (every hole and welch plugs were removed) all new jets. Floats are set to level with carb if held upside down and the drop is 7/8 of a inch. motor has to idle at 1300 rpms or it wants to die. Gonna put champion plugs in to see if this helps. boat is now running 35mph at 5200 rpm's. Gonna try a lync and sync this week sometime.
 
Get the original plug wires back in together with the champion plugs recommended or soon your powerpacks will be history.
Get the link and synch right, and note the part about 'pick-up' timing which is not the same as idle timing!!!!
Max advance ok if you are running premium fuel??
From the look of it you are running an 'old' type SST propeller with STERN lift?
That rig I would have equipped with a RAKER (bow lift)14 x 18, and most likely lifted the engine to 2-2,5" above.
 
well we took the boat out and did the link n sync. Runs pretty good except it seems to load up at idle or low speeds. When you take off it kinda sputters untill you get going alittle. Should i try 1 hotter plug? Fuel is mixed 50:1 and using havoline outboard oil. There is no carb adjustments on these carbs, I have the floats set level when held upside down and turn them over the drop is set at 7/8. Timing is all set right. Any ideas?
 
Did you replace the Anti syphon valve, you need to hook up a vaccuum gauge inline and rule out a fuel suction problem, you should not see more than 4hg when throttle if it jumps up to 5-7 and especially fluctuating you know you are getting a fuel restriction, so rule that out.
 
all valves are new along with fuel pumps and lines. Just went through the motor with all new gaskets. Also went through carbs with new jets and needle n seats
 
Try to 'adjust' the pick-up timing, by letting the timing advance 3 degrees MORE before the carbs starts to open.
You may make a quick-test, by just loosening the roller and let the mark on the cam pass 3mm before the carbs start to open.
Which plugs are you using?
 
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