DT75 - can't get it to stay running

[Gas Giant]

Re: DT75 - can't get it to stay running

I did have smoke from the exhaust and what I believe was oily water....the boat is in my yard, (driveway is a bit steep and, irritatingly enough, there is no hose spigot near it) so its hard to tell exactly if it was oily.

But I will check the manual on getting the pump primed. The oil tank is nearly full of oil, so this could get messy

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Well, I decided to pull the head to look for problems with the gasket as I could find no other problems anywhere else, and managed to snap two of the cylinder head bolts. I don't have the tools or skill to deal with this problem. I really don't know what to do at this point.

On an unrelated note, anyone have a 70-85 hp outboard they want to donate to the cause? I'll trade you a haunted Suzuki DT75 that is most likely a parts engine ;-)

 

[mphelle8vld]

Re: DT75 - can't get it to stay running

If you don't mind adding a whale tail and painting the motor white....

http://cgi.ebay.com/ebaymotors/1988...0572535QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

 

[James R]

Re: DT75 - can't get it to stay running

Not unusual to break a bolt on the Suzuki. I have had a bunch of them. Stubs are often visible and can be removed.
You may well have someone local who has the experience. Heat will be needed. Best way I have found, if the stub is at or just below the surface, is to weld the inside of a steel washer to the stub, weld a bolt to the washer and use an impact wrench to screw the stub out while it is still hot. If the stub is above the surface clean it up and weld a steel nut to it. Run a tap down the thread and you're good to go. A Mig welder is best.
What did the head removal reveal?
Don't despair you're almost there.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

That would be perfect.....unfortunately, I am broke until tax time......sigh.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

I haven't gotten the head off yet...the one last bolt down by the fuel filter can't be reached with any sockets I have...which means a trip to the store to buy a 14mm wrench. The studs should be visible once the head is removed. I have a Miller MIG welder with a gas bottle, but not a whole lot of experience with it. No impact wrench unfortunately....

I shined a flashlight in the #2 hole, but couldn't make out much.

 

[James R]

Re: DT75 - can't get it to stay running

Be sure to get a good quality wrench. A cheap Chinese thing will just round off the bolt head.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Got the last one out using a really old Craftsman wrench my dad had. From when they were made in the USA. I think.

But, the head isn't going to budge, due to the two bolts that broke off flush with the head and the two other bolts that broke off right where the threads began.

Not too sure how to remove it at this point. Dynamite perhaps? My welder is meant for sheet metal and its unlikely that its up to the task of welding something strong enough to stick an impact wrench on.

 

[James R]

Re: DT75 - can't get it to stay running

Probably need to apply some heat to break the corrosion at each bolt then tap carefully with a soft face mallet to loosen the head up. Map gas may be hot enough. It will take a little patience. I have done a few. Try to leave the bolt stubs intact to help with removal. Don't forget you will need heat to break the corrosion when removing the stubs. You will definitely need more heat than the map gas can produce at that stage.
When you get to putting the head bolts back apply some anti seize on the threads and the shanks. Don't forget to clean all the threads with a Tap.
Sorry to say but Suzuki bolts are a hard grade stainless. This makes them more prone to corrosion especially when exposed to salt water and air.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Thanks for the suggestion. It may be a week or two before i start working on this engine again, mainly because I got so frustrated last time....lol.

I'll try to get the head off with some heat, mainly because I am very curious as to whats going on with my compression. Hopefully I can get it loose.

As far as the studs go, I may seek professional help with those (If I can find help locally). I don't want to screw up my block by drilling badly (Which I am known for......) as two of the bolts broke at the top of the threads instead of just below the head of the bolt, and knowing my luck the studs are going to refuse to come loose.

 

[stylesabu]

Re: DT75 - can't get it to stay running

I have a DT75 that i got out of salt water that i dis-assembled and had same problem with corrosion. heat will be nessary, try to get some type of wedge between power head and body.then while heating tap on areas where bolts broke. most auto shops have torches, you might try one of them.i do have this motor that I'm parting out if you need parts, I was going to sell it with the boat, but my other motor runs strong. so I'll just part it out.

 

[stylesabu]

Re: DT75 - can't get it to stay running

picture of my other dt75

 

[Gas Giant]

Re: DT75 - can't get it to stay running

stylesabu,

Thanks for the advice. I'll let you know about parts; not sure what I need yet.

 

[stylesabu]

Re: DT75 - can't get it to stay running

i have everything except exhaust cover, including controll box with cables, can send serial number if you need

 

[James R]

Re: DT75 - can't get it to stay running

You are wise not to attempt drilling. The drill usually wanders and then the block will be an issue. Using the weld technique that I suggested in one of my earlier reply's will certainly be the most effective and the safest.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Most of you probably aren't interested anymore, but I did find someone locally who can drill the bolts out. Problem is finding a weekend where he isn't busy!

I'll keep you guys posted on what happens, so if this thread pops up in someone's search years from now, the problem was at least identified!

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Well, after a few hour of fighting, the cylinder head came off.

Turns out the head gasket was fine and the cylinder walls look good - no scoring, rust or cracks, and the pistons look good. I suppose this is good news.

Of course, the bad news is that now I have to continue my search for what went wrong! Bad reed maybe? How do you check a reed valve?

 

[99yam40]

Re: DT75 - can't get it to stay running

Did you check compression with a different gauge to make sure all were truly low?
I do not think bad reeds will give low compression

 

[Gas Giant]

Re: DT75 - can't get it to stay running

No, I didn't check it again, will have to wait until its back together to do it again.

 

[Gas Giant]

Re: DT75 - can't get it to stay running

Well I looked a little closer, this time with a flashlight, and there is some scoring evident on the cylinder walls. Guess its either time to replace it with a different motor, or start a "Rebuilding a DT75" post!