85 Force problem

[frmboybuck]

Heres a weird problem(to me). I got this motor running really good with the muffs. It runs great out of the water. Well I took it to the lake this morning to try out a prop and it ran like crap in the water. Had a heck of a time getting it started and it would'nt idle. I finally got it in gear and moving. It ran at WOT for a minute or so and I backed it off to slow down and it died. Heck of a time getting it started again. It did this about 3 times and I decided to go home. Got it pulled up on the trailer by hand and went home. I put the muffs on it at home and I couldnt ask for it to run any better....Perfect!<br />Whats up with this???? Take it easy on me fellas....I know squat about boats<br />Buck

 

[eurolarva]

Re: 85 Force problem

When your motor is in the water there is backpressure that you dont get from the muffs. The problem you are having could be electical or you could have a blown head gasket. You should have a compression test done on each cylinder and post those numbers here. If you cant do a compression test pull the spark plugs out and look at the tips and see if either one of them looks clean. A clean plug is a bad sign. Chances are you are only firing on one cylinder. The clean plug is the culprit. The compression test will tell you if it is an electrical problem or you are looking at a blown head gasket.

 

[frmboybuck]

Re: 85 Force problem

Well last night I got to thinking about what I posted and then it dawned on me that I have backpressure in the water. Well I did a compression check today and this is what I got. <br />Cylinder 1: 110<br />" " 2: 100<br />" " 3: 120<br />Plugs looked fine and werent clean so the head gasket idea is out. I have good fire from all 3 coils. I thought of a fuel problem but the way it runs with the muffs on I dont think it can be that. Any other ideas????? Id like to get it going good, sell it and buy a nice fish and ski. Hopefully ill get it going.<br />Buck

 

[OBJ]

Re: 85 Force problem

Buck...did you just get this motor? Has it been setting for a long time? You could be looking at some varnish in the carbs doing a little plugging up here and there.<br /><br />The #2 cylinder is a little low if you look at the 10 to 15% difference. Do a decarb and see if the cylinders come a little closer together.

 

[eurolarva]

Re: 85 Force problem

I agree with OBJ on the number two cylinder. Try testing for spark with all plugs out of the cylinders. Then put dummy plugs or old plugs in the cylinders and test your spark again. This could be fuel related but it sounds more like a head or a week coil.

 

[frmboybuck]

Re: 85 Force problem

It has been sitting for over a year. I havent ran any carb cleaner through it yet. I did put fresh gas in it and such. I will try to check the spark again. Why would it run great on the muffs but like crap in the water??? That shouldnt have anything toi do with the spark should it?? How do I do a decarb???? I really appreciate the help guys. Keep it coming<br />Buck

 

[frmboybuck]

Re: 85 Force problem

TTT

 

[eurolarva]

Re: 85 Force problem

The reason is could be spark is that you may only be firing on two cylinders. A motor will run fine that way until you give it back pressure by putting it in the water. Number 2 cylinder is showing signs of a blown head gasket. This can be caused by motor running lean, not enough oil in the gas or from overheating. Decarb will sometimes help compression.

 

[frmboybuck]

Re: 85 Force problem

Thanks....Im going to decarb it tonight. I bought some Seafoam today. I got spark on all 3 cylinders....good hot spark. Fresh gas mixed 50:1. Im going to but a plastic barrel filled with water around the motor so it has back pressure this time. Ill see what happens after the Decarb<br />Buck

 

[frmboybuck]

Re: 85 Force problem

Did the decarb. It helped my compression some. Now my readings are<br />Cylinder 1: 140<br />" " 2: 115<br />" " 3: 140<br />Didnt have time to put the barrel around the motor. Ill do that tonight. It still runs good on the muffs but I have my doubts in the water. I pulled the wires off of the plugs at different times last night while it was running. Its deffinatley firing an all 3 cylinders.<br />Buck

 

[eurolarva]

Re: 85 Force problem

Chances are you have a blown head gasket. Compression on number two is bad. All cylinders should be less then 10 digits from one another. You will have to take the head gasket off and see if there is any cylinder or piston damage. Head gaskets arent too expensive as long as nothing else is damaged. Also post your model number and I will get you a part number for the head gasket.

 

[frmboybuck]

Re: 85 Force problem

I checked compression again this evening when the motor was cold. Took all the plugs out and got <br />140<br />120<br />140 <br />Its getting a little closer. Is it acceptable??<br />I put it in the river tonight and left it on the trailer because there is alot of current. Its ran great.I ran it at WOT for a while and it ran really good. When I back it off from WOT it smokes a little. Whats causing that??? Just running a little rich? I did notice when I was about 3/4 throttle and went to WOT, it hesitated a little Not sure why and it wasnt bad but it did have a slight hesitation to it. I am going back to the lake on Sat morning and going to run the heck out of it....Hopefully<br />Thanks<br />Buck

 

[frmboybuck]

Re: 85 Force problem

Ok took it back to the lake this morning and the boat ran fairly well. It ran great at WOT. Does 35MPH at WOT for a 16' bayliner with 85HP force sound about right??? It comes out of the hole well and planes out fairly fast. The only problem I am really having is when I slow down the motor boggs down and dies. It will start right back up. To me it acts like it floods itself out when you back the throttle off. It does smoke alot on the water. It dosent smoke at all in the yard on the muffs but it smokes like crazy at an idle in the water. At WOT it dosent smoke at all but as soon as I slow down it smokes like crazy and dies. I have new gasm mixed at 50:1 with 2 cycle oil. IS the 50:1 correct??? Any suggestions on what to try next???? I dont have a manual yet for this thing....I need to get one <br />Thanks for all the help you guys have given me so far....I really appreciate it<br />Buck

 

[eurolarva]

Re: 85 Force problem

YOur carbs may be burning rich. I still think you have a problem with cylinder number two. When you goose the throttle from slow to fast. If motor dies it is too lean. If it stumbles it is too rich. You want the motor to be slightly rich. <br /><br />Take your number two spark plug out and see if it looks like the other two plugs. If it is clean you are getting water in the cylinder and have a blown head gasket. Try doing another warm compression test. Do it first like you did in your earlier post. Then squirt some oil into the number two cylinder and see if the number goes up.

 

[frmboybuck]

Re: 85 Force problem

OK thanks eurolarva....Ill try that when it stops raining out. When I goose it it takes right off....My problem is when Im slowing down. From WOT to idle it dies.<br />Thanks<br />Buck

 

[frmboybuck]

Re: 85 Force problem

ok this morning I let the lotor warm up good in the yard. I did a compression check on the motor again and got this<br />1-145<br />2-125<br />3-145<br />I squirted some transmission fluid in the #2 cylinder and checked it again and got 180-190 on that cylinder. It does smoke alot. What would make it smoke like this. It dosent smoke at WOT but from idle to mid range it really smokes. My plugs were still dirty when I took them out. Also while messing around I broke the (I assume) temp sensor. It screws into the head right by the #1 cylinder. Anyone know the part # of it?<br />Thanks<br />Buck

 

[eurolarva]

Re: 85 Force problem

Post your model number and I will get you a parts blow up of your motor. When you say smoking a lot are you sure it is smoke and not steam? When you say your plugs are dirty are all of them dirty including number 2. Here is what I think is happening. Your number two cylinder is getting water because of a leak in you head gasket. Your motor is hot so when the water is getting into your number two cylinder it is boiling and creating steam. I dont know for sure this is just a guess. Post your model number and I will post a link for you for parts.

 

[frmboybuck]

Re: 85 Force problem

Thanks Eurolarva. I will get that model# for you today. Im also going to pull the head and have a look at the gasket and head. Yes the #2 spark plug is just as dirty as the rest of them. Im pretty sure it is smoke but heck Ive been wrong once before. lol Thanks for the info<br />Buck

 

[frmboybuck]

Re: 85 Force problem

the model# of my motor is 856X4L. I took the head gasket off and it had some of the gasket material torn between a couple holes in the water jacket but it didnt seem to be bad aroubd the cylinder. Ill buy a new one and put it back together with that....Sure hope it cures my problem but I have my doubts<br />Buck

 

[eurolarva]

Re: 85 Force problem

Here is a link to the parts for your motor. It appears to be a 1984 856X4L The part numbers here are merc numbers so if you find anything you need you should be able to get them from your local merc dealer. Good luck