Help on 1990 150hp Force

T-rain

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I have a Crest Pontoon. I had always wanted a bigger motor than the 75hp that came with it. I purchased a 150hp 1990 force to put on it.I had the paperwork where the powerhead had all been replaced. I had it put on the boat about 6 yrs ago; due to various life situations, I wasnt able to use it until late last summer. Took it out in the fall, ran great except the idle needed setup. Well, took it to the big lake, backed off the trailer and it started cutting out, and smoke rolling from the cowl. Finally got it back to shore, it was extremely hot to say the least. Found out later the waterpump had disentergrated due to dry rot. Well over the winter rebuilt the carbs and installed new waterpump. Got it cleaned up and ready to go a couple weeks ago. The starter would turn, then would semi lock up and start smoking. I finally got it started and water was shooting out around the head gasket. Went around and tightened the bolts, which stopped the water leakage. Well, I thought maybe the starter was bad? Replaced the starter, battery, and solenoid. I finally got it started and running on muffs...idled and ran good, sounded good when revving up the throttle. But, now wont start. It will turnover great at first, then as compression builds up it starts locking up and smoking the starter. Pulled the plugs, the bottom 4 had oil and fuel on them, the top was appeared to almost be rusty. Well, I checked compression. All the bottom 4 cylinders were exactly 130psi to the tee. The top #5 cylinder was only 110 psi. I pulled the head gasket cover off, fully expecting to see a burnt up top piston. Much to my surprise it looked brand new. Some of the top head bolts had water come out of them when i removed them. I guess my first and main question is: Would replacing the head gasket solve my problem, or do you guys think i have other issues?? I have included some pics of what it looks like. Im so so as a mechanic and really dont have the extra money to take it to a marine mechanic to pay a fortune. I have thought about going and putting my old motor back on and being done with this thing, but I have so much time and money tied up in it already..sorry for the long post..any help would be greatly appreciated!!!! Also, there are small rubberlike tubes between the cylinders. the one between the top and #4 was burnt up, the others are all stopped up with something which appears to be hard water deposits? Is this a problem and what are they? I have included pics of them as well?
 

Jiggz

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Anytime a outboard motor or maybe any boat motor for that matter comes out of long slumber, three things need to be opened and inspected and replaced as required. Water impeller needs to be replaced regardless of its physical appearance. The lower unit gear oil needs to be replaced also. Carbs needs to be opened, inspected and cleaned. Spark plugs needs to be replaced depending how long it has been in storage.

In your situation, you need to replace the head gasket and do the correct torque and pattern on the head bolts. The fact there was water shooting out of the head (which you stopped by tightening the head bolts) tells me it was never properly torqued to start with.

As for the disintegrated impeller, it is most likely some of the parts got clogged into the water ports. And yes, after being in storage without proper lay up water deposits will develop.

Finally, you need to clean all battery terminal connections, starter and most especially the negative cable connected to the engine block. Simple visual check is not good enough. You have to disconnect, wire brush and sand paper all mating surfaces and re-tightened.
 

jerryjerry05

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After 3 posts you can add pics. unless you use a photo sharing site.

​The burnt water diverter if it's still there? leave it unless it falls out.
​You can fab a new if you need.

​Before I'd buy a new gasket, I'd goop the old one with sillycone and check the compression.

​Check the head for being warped? a straight edge helps.Or a big piece of glass.

Sometimes the difference in comp can make the starter drag.
 

T-rain

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Thanks guys for the replies...I talked to a friend today who previously was a marine mechanic/shop owner...when i explained a few things to him he told me something which made perfect sense that I would've never thought of...The top sparkplug was clean, as was the piston. I explained the starter would roll the motor over as it should for awhile, then it was like it was building up compression and locking up the motor/starter. He said check the coil pack on that cylinder and see if it was firing. He was thinking the cylinder was filling up with fuel, which would explain the piston pressure. He also said lay the head on a glass table to see if it was warped. Also, there is a small burnt area on the ring of the top cylinder on the head gasket? I will post pics as soon as I post 3 times and am eligible..So those little black tubes are water diverters?
 

Jiggz

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"He was thinking the cylinder was filling up with fuel, which would explain the piston pressure."

I've been with this forum for almost 8 years and this is the first time I heard of this from a marine mechanic, at least with two cycle engines. I've heard of hydraulic lock on 4 cycle engines though.
 

jerryjerry05

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The 2cycle. can't fill with fuel.
​Yup water diverter, if it wasn't there the flow wouldn't go to all the spots on the motor and cause hot spots.

Usually if the plug is clean it isn't firing.
​Or on the lower cylinders if it's a cyl. that runs one of the 2 fuel pumps it could have a bad diaphragm.
But this is a top cyl. and probably not firing.
Or not firing under compression???

​Any fuel coming out of the carbs when running? "reeds"

Check all connections and clean/replace all wire connectors.
The trigger wires are very thin and break easily.
​The shrink wrap holds it real tight and seem like its OK!!
But pull on the end going into the buss barr and see if the #1 pulls out??
I usually just replace them all with new connectors when I'm working on the electrical system.
​A bad ground or bad coil even a pack can cause the no fire.
 

T-rain

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Thanks again guys...Im having trouble finding a head gasket online for this particular motor? So you in guys expert opinions, do you think my low compression on the top cylinder would or could be strictly from a blown headgasket? Im still struggling with what is locking up the motor after trying to crank it? I know just enough to be dangerous..LOL Could there be an exhaust valve sticking?
 

Jiggz

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There are no valves on this 2 cycle motors, instead it's all intake and exhaust ports. So no sticky valves except maybe for the reeds.

You now have three posts and should be able to post some pics of the head gasket, the cylinder head inside and the cylinder top. In this case, we can do a post mortem analysis. If the gasket is still in very good shape you can probably reuse it until you can get a replacement. Assuming you have good spark on #1 cylinder (cylinders are numbered from top to bottom, 1 to 5), there is good chance you might have damaged reed.

To check this dismount the top cylinder carb and behind it is a reed V block.
 

T-rain

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Thanks again guys!!! Your replies are so appreciated!! The one pic shows the burnt place on the head gasket; as far as I can tell, the rest of it seems to be ok. So do you guys think the reeds could be the reason its building up the compression? Im just afraid if i replace the head gasket Im still gonna have the problem of it not starting due to locking up the starter with the built of compression?
 

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T-rain

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Anyone have any comments on the pics?? Im sure there is more info there for someone who knows what theyre looking at?? I can see the classic blown head gasket. My main concern still is in my mind I still cant understand how the blown head gasket would keep building up compression and locking the starter up?? Im sorry Im so thickheaded. I just hate to put a $100 head gasket on and still have the same problem...
 

T-rain

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Well, to follow up. I replaced the blown head gasket, and found coil pack one to be bad. replaced it. Cured the starting problem; no more locking up the starter, flywheel spins freely now. Took it out and ran it on the lake, ran great for an hour or so. It would start with a flick of the key. But wait, there's more! Put it on the trailer. This was Sunday. Went back down Friday to use again. The POS wont start now. At first it hit a couple times like it was gonna start, but now it just cranks and cranks, but wont even attempt to start. Ive done the obvious; full tank of fuel. Charged battery to max..ive taken the gas lines off and it appears plenty of fuel is coming from the fuel pumps. checked compression on all cylinders (good) all plugs seem to have spark, but it seems kinda weak? When we pull the plugs, there seems no sign of fuel making it to the cylinders. Im thinking either have a clogged up carb, bad fuel pump, or a spark issue?? Im so frustrated with this motor!!
 

pnwboat

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Need to know which ignition system you have. Do you have the sky blue coils, with the three CD Modules, or do you have the dark blue coils almost black in color with the Switch Box ignition?
 

jerryjerry05

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The flywheel?? What torque on the top nut?
The "nylock nut" the plastic might let go and back off.
Test the timing to see if the key sheared.

Above the top carb is a timing mark
On the flywheel, there are marks, 3 close together and 1 single mark.
​Remove the plugs, long skinny screwdriver inserted in the top hole.rotate the flywheel till the screwey is pushed out as far as it can go.
The single mark should align with the timing mark or be close.

The kill switch not on?

​The build up of compression and the motor not turning over.
IF??? you have low compression on 1 cyl. then the starter has trouble turning the flywheel.
 

T-rain

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Im still torn on whether I have a low spark issue, or fuel delivery problem? Would putting gas into the cylinders and see if it hits be possible? How would one go about doing that??
 

kbh121956

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Jun 30, 2013
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Use a spray bottle gas/oil mix. Crank the engine over and give the carbs a squirt, see if she'll fire. Does your primer bulb get hard when you squeeze it?
 

T-rain

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yes the primer bulb gets hard with 3*4 pumps..thanks, Ill try that when i get off work...
 

Jiggz

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Just a reminder, the engine should be in down position (meaning not tilted) to get it started. Make sure the ilde mixture screws are all set to 1 ~ 1 1/2 turn out from seated.

Additionally, install a clear fuel filter (Wally mart has the G2 Fram for less than $5) between the fuel pump outlet and the carbs inlet. This is more of a troubleshooting tool than an actual fuel filter. When priming, the clear fuel filter should at least be 3/4 full before the primer bulb gets hard.

Make sure you use the proper starting procedures when cold starting, i.e. prime, fast idle on the throttle and choke while starting. Be careful with the choke as it can flood the carbs very quickly. Usually, while cranking and choking, the engine will either "cough" or start. Anyways, if it didn't start and it only coughs, you should try cranking it again without choking it to avoid flooding.

After two tries and it still would not start but continues to cough, then try choking it again.

As soon as the motor starts, lower the fast idle after a few seconds to about half way. And after about 30~60 seconds it should be warm enough and then place the throttle in neutral.
 

jerryjerry05

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Most outboards don't need starting fluid.
​BUT!! to help diagnose the problem a shot of it will tell you if you have a fuel delivery or spark problem.

Did you check the timing like I suggested?

You have a spark tester? $7 most auto parts store.
 

T-rain

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Thanks guys...just getting home from work (night shift) I will try to check out all the above ideas. What is curious about it all is we used it on sunday; started right up everytime. Flick of the key and it would start..ran it on the lake for a couple hours..put it on the trailer. went back down the following Friday..It hit a couple times like it was gonna start, then that was it.. now just cranks and cranks and cranks, but not hitting at all? I ordered a Clymer manual for it yesterday. I will buy the clear fuel filter and try that, check the timing and get the spark tester..Would a kill switch wire even allow it to crank. I did install a stereo that morning. Would there be a possibility I pulled a wire loose somewhere??
 
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