Helping Neighborhood kid with overheating 30hp yamie - need to ID the motor

**CircleHook** · 07-24-2017, 02:31 PM

Neighborhood kid saved up his pennies from mowing grass and odd jobs to buy a a tiller motor- it is suspose to be a 30hp yamie - it is overheating at idle-
No SN # Please look at pictures and see if you have any idea what this actually is.

**RSWORDS** · 07-24-2017, 03:32 PM

Try a 1990. It looks to be around that. They didn't change much over the year as fat as water pumps go. Pull it apart. Compare on boats.net

**RSWORDS** · 07-24-2017, 11:00 PM

Pull the lower and take some pics. I'll get you some.part numbers

**Wayne Cammidge** · 07-25-2017, 05:56 AM

It is a 30 A
1981-1986
Easiest motor in the world to work on
While the lower is off try blowing thru the water system up the water pipe with both air from your mouth with a short pipe attached and a garden hose attached to see if the block is blocked up.
Salt water does nasty things to those engines
Most likely will need to take off the cylinder head and side cover gaskets plus clean out below the powerhead.
Just about every bolt you touch is going to break, so be prepared.
Need to drill out and thread repair just about every bolt.
Use decent grease on the bolts when you re-assemble to stop it happening again
Cost of labour would be prohibitive, but labour of love will make a very nice motor when you are done.

**CircleHook** · 07-25-2017, 06:17 AM

Thanks Guys- No salt- ran compression check last evening - 0 on top - 120 on lower- pulled head- gasket blown badly - however no other visible damage- head bolts were not as tight as I would have expected. Cylinder wall look pretty good. If these little motors are as tough as everybody says- I would expect to put a head gasket on and send him to the pond. Need gasket ID and head bolt torque- I will use the 30A 1981-1896 to search.

**FMP** · 07-25-2017, 06:41 AM

Maybe take a few off the head , flat and true.

**Wayne Cammidge** · 07-25-2017, 07:13 AM

689-11181-01 Head gasket for 1986

**CircleHook** · 07-26-2017, 06:13 AM

Originally Posted by Wayne Cammidge

689-11181-01 Head gasket for 1986

Any idea of torque for head bolts? Thanks Guys-

**Wayne Cammidge** · 07-26-2017, 06:56 AM

28 Nm

**CircleHook** · 07-28-2017, 07:42 AM

Originally Posted by Wayne Cammidge

28 Nm

thanks - getting to lower bolts on the head is a tight fit - will the lower cowl un-bolt and drop down?

**Wayne Cammidge** · 07-28-2017, 08:51 AM

It will un bolt, but mainly lifts up.
Not sure if it will give you enough space to get to the bolts from below.
Do not think so.
Base gasket is cheap, and then you know what is below.

**olboatman** · 07-28-2017, 07:21 PM

If I am correct that is the same mota that Merc sold under their Mariner brand during those yrs. A friend had one and it was a stone crusher!!! Gary

**Wayne Cammidge** · 07-29-2017, 02:03 AM

That's it
Mariner and Yamaha were identical
Top Cowl on some models were different and associated with that the pull start guide that went through the cowling was different