Engine locks up when warm Cold does fine

[mallen]

Re: Engine locks up when warm Cold does fine

OK pulled the thermostats and checked them. They both open well when heated. Opened up the water passages on the back of the motor and they seem clean. I don't think it is a dirty passage problem. Next step is to pull the impeller and see what it looks like... Could someone tell me if the 4 89psi cylinders are within spec on this particulart engine. The way I see it I have two cylinders with problems. The 62 and the 70.

 

[Walker]

Re: Engine locks up when warm Cold does fine

89 is fine for that motor. Time to pull the head/heads to see what kind of damage you have in there. Which cylinders are low. Same side?

 

[Silvertip]

Re: Engine locks up when warm Cold does fine

Get manuals right here on iBoats, your local dealer, Amazon, eBay, or do an on-line search. Most service manuals will cover an engine series that may span a number of years. Youmay even find one at the public library.

 

[mallen]

Re: Engine locks up when warm Cold does fine

Yes, the cylinders are both on the same side.. Looking at the motor from the stern of the boat they are the top two on the right bank. The worst is the top and the second bad one is the next one down. That is where I started my search. I haven't seen the impeller yet but wouldn't that cause all of the cylinders to have the same problem not just those top two.

 

[R.Johnson]

Re: Engine locks up when warm Cold does fine

Pull the cylinder heads. That will give you the whole story of which way to go. Don't worry about the impellor at this time. Carefully look at all 6 cylinders, not just the two low one's.

 

[mallen]

Re: Engine locks up when warm Cold does fine

OK ordered a manual. Pulled the heads. Vertical scoring on the two low cylinders. The other 4 were fine. No visible top damage to the pistons of the scored cylinders however you can't see the sides of these unless you remove the cylinders. So condition of rings unknown as well. The vertical scoring could easily be taken down with a hone. All passages that I could see for cooling look fine. I'm stumped what the heck caused this.

 

[R.Johnson]

Re: Engine locks up when warm Cold does fine

If that engine was locking up, and the compression was that low, there has to be a problem somewhere. Yhe engine has to come apart, so let us know what you find,

 

[papasage]

Re: Engine locks up when warm Cold does fine

sounds like the carb that feeds that side is running lean . i think if it gits that hot it would be steaming and a buzer would go off . check the heat warning buzer and see if it is working. should be a beigh wire that is attatched to the head . i had a mercuray that was a stream comming out of the pe tube and it still ran hot . it would run mor than a few yards .

 

[Andrec4016]

Re: Engine locks up when warm Cold does fine

I have a dumb quetion here, how long have you had this boat, did you just get this boat, if so did someone rebuild engine before buying.. The reason I'm asking is I had same simptoms of seizing after warming up.. the problem with mine was improper overhaul.. the guy before me replaced all bearings and rings but did not bore out cylinders for new rings being a 83' the cylinders wear down in a oval shape if you put in new round rings then you get seized up after running a few minutes.. a quick check from the top of cylinders with calipers will confirm this, its worth checking.. if so the only fix is to bore out and replace with proper size rings..

 

[Silvertip]

Re: Engine locks up when warm Cold does fine

If the cylinders are scored bad enough that you can catch your fingernail on them, its rebore time. Chances are the pistons are scored as well.

 

[mallen]

Re: Engine locks up when warm Cold does fine

OK answers backwards... You can't catch your fingernails in the scores. Second yes I just purchased however. NO work was done inside the engine recently. There are six carbs on this engine one for each cylinder. So that would mean that two of the carbs are running lean, unlikely. I am waiting on the manual to do the tear down. I can't tell where to start taking it apart until I see where it comes apart

 

[mallen]

Re: Engine locks up when warm Cold does fine

More info.... When I pulled the head off of the low psi side one of the bolts was only hand tight on the head. Absolutely no torque on it. It was only one. I don't think that would effect it with just one. What do you think?

 

[mallen]

Re: Engine locks up when warm Cold does fine

Dumb question here.... I see the wire going to the head for the heat sensor but don't understand why I never heard any buzzer? Is there a warning buzzer for overheating or some sort of light or something. I had no idea anything was wrong till it locked. As I said the motor sounded fine till it locked.