running rough at idle

[ferdly1]

Noticed motor idling rough. Did compression test. 120 psi both cylinders. when i pulled plugs were spotless. So i figured i had bad headgaskets. Replaced head gasket even though i didnt see anything wrong with gasket. I swear thats cleanest pistons i have ever seen. Had this boat 20 years. Its a 1997 40hp elpt Force. I think water is getting in some how. I noticed a small amaount of water leaking out one bolt on exhaust port plate on right side of motor just behind the starter. That big plate. Just tiny drop oozing out . Could that be the culprit. Also have exhaust smoke coming into motor i guess form adapter plate. Could water be coming in that way? Boat runs good at higher speeds but rough at low speed 5mph or less and idle. Any suggestions would be welcome.

 

[ferdly1]

i think i will remove exhaust plate. if there is a leak there makes sense i would have clean pistons

 

[Nordin]

Yes, if the stainless steel plate or some of the gaskets at the exhaust cover plate are leaking you will have water intrusion to the cylinders.
If your clean piston/head is the bottom cylinder check the lower crank shaft seal too.

 

[ferdly1]

both pistons are clean. i looked up lower crank shaft seal. there is a needle bearing there- should I change that if so is i possible to remove without opening crankcase

 

[Nordin]

If the needle bearing is okey do not change it.
You have to split the crank case to change the bearing cause the bearing has a locating pin in the crank case.
If both pistons are clean the lower seal is not the culprit.

 

[ferdly1]

hey thanks - was gonna pull motor - guess i will just order those 2 gaskets for cover plate- was thinking of changing gaskets on adapter plate because of all the smoke getting into motor- thanks a bunch

 

[ferdly1]

i thought problem was electrical- i chnaged trigger and coils- then i did the shade tree machanic trick- run motor in dark looking for sparks non found- then i spotted that tiny leak -it got me to thinking- at 69 not as quick as i use to be figuring this stuff out-- i need all the help i can get now- thanks again

 

[ferdly1]

deleted

 

[jerryjerry05]

Try the starting fluid test??
Start motor, spray SF around the intake side of the motor, around the carb bases, under the ignition components and around the port covers.
A miss like that can be a bad gasket under the port cover that holds the fuel pump or the other cover.
One small backfire, cough, stutter can blow a port cover gasket and that's really hard to detect.

 

[Nordin]

If you get exhaust in to the cowl the gasket under the power head to the leg may leak.
It can also be the gaskets for the exhaust cover or both of them.

 

[ferdly1]

I attempted to pull port cover plate off. Three of the bottom bolts broke. I was very careful but didnt matter and of coarse they broke off 1 !/2 to 2 inches down where I cant get to them. The cover is off but the intermediate plate is stuck on. Next question. Is there a good machine shop in Florida where i can take it or ship it to have bolts removed and tapped. I am located in Tallahassee. I tried a machine shop here once. I wont use them again. Oh. Every single bolt that came out was wet and covered with oil or sludge. I believe i found the problem

 

[ferdly1]

ok update- the break down says there are 15 bolts I count 16. These bolts should go all the way thru the intermediate plate and screw into the block. For some reason I have 2 bolts one on top and a second directly below it that have a 1 inch 1/4 20 bolt screwed into intermediate cover why makes no sense to me. So it looks like the intermediate plate is stuck on broken bolts - however now i think i can break it loose with a good penetrating fluid. Any suggestions. After that hopefully the bolts will unscrew. Might also try heat however that big metal plate will act like one big heat sink. Worthh a shot. Anyone who has had this problem before dont hesitate to chime in.

 

[Nordin]

These bolts for the exhaust cover are a PIA to remove.
They are small 1/4 in and will snap very easy.
Especially the bolts in the lower part of the cover, they are exposed to the hot exhaust and will stuck really hard to the power head.
Looking at the exploding view there should be 15 bolts which are 2,5 in long and 2 bolts which are 3/4 in long.
From my experience the only way to remove the broken bolts is to pull the power head from the mid leg, drill them out and retap.

 

[ferdly1]

yes i had to pull the motor. And thanks for the update. There are 2 3/4 bolts. and 15 2.5 inch long bolts of which to are broke off in the inter mediate plate. Trying to get those two worked loose. not having much luck with penetrating fluid. gonna remove adapter plate and hoping i can tap intermediate plate from bottom if there is something to grab. thanks for your help. seems someone had worked on this motor years ago before i got it. I bought it in 2001 and its a 97. There was silicone sealer on the gaskets , which really didnt stick to anything really well. Should i use some kinda rtv sealer on theses gaskets?
And thanks for the help!

 

[ferdly1]

well looks like you are right- penetrating fluid nor heats works- gonna have to drill it- No way to put on drill press so will have to do by hand- also figured this plate can or will be sacrificed. as long as i don't screw up the block. Have to buy corded drill. My cordless useless for stuff like this.

 

[ferdly1]

Well i got the plate off. What a pain. Also if you gonna drill get cobalt drill bits forget titanium.Also drill slow. I bought a cheap corded drill at harbor freight. But i could have done this with cordless drill. i have a half inch of bolt sticking out of block I will tackle that tommorrow. Although I could reuse that plate gonna get another. That was the best drilling job I ever did.

 

[Nordin]

Are you going to replace both gaskets 8268711 and 826738?
No extra liquid seal such as RTV are needed.
I would put some spots of liquid seal at the gaskets just to hold them in place when you reinstall the parts/power head.

 

[ferdly1]

Finally got all gaskets in. How do i get that dried gasket material off. Its really on there. I plan on replacing both gaskets for exhaust cover plate. both gaskets for adapter and seal-. I also want to change Exhaust gasket. Just wondering if i take 4 bolts off holding cowl and swing cowl to the side with cobles attached, if i can get to the exhaust gasket. Been scraping gasket off with razor. just wondering if theres a better way.

 

[Nordin]

Removing old gaskets i use razor blades or a papper knife with a thin blade.
There are gasket remove tools at the tool market, they work but be careful when you working on aluminium alloy.
Easy to make scraps.

 

[ferdly1]

Razor blades just wouldnt cut it. So i bought an air powered angle grinder and some of those round scotch bright pads. that did it. You have to hold grinder perpendicular to work and keep it moving. Dont apply any pressure , let it do the work. Saw a you tube video, thought i would try it.