hey guys. picked up a 1982 Larson/arctic marine sundance 12' jetboat the other day. I took it out for the first time today and it started overheating within like 5 minutes. before that it wouldn't rev above 4700rpm and it was topping out at like 19mph and didnt seem like it was fully on plane. When I got it home I found the coolant line going into the block was completely plugged. some compressed air and it was flowing well again. its still running on both cylinders and starts fairly easy so looks like a dodged a bullet. hoping the next test drive goes a bit longer
Anyways this motor/jet is used on early model wetbikes. I believe its a powerhead from a 82 dt50 going by pictures I found online. Now ive read someone with a similar boat will rev up to 6000rpm and he gets about 31mph from it. Can anyone think of anything on this motor I should look at that would impede performance? It starts extremely easy and sounds very smooth at idle. it does idle a bit high (2100ish rpm). Issues that im currently dealing with it has a full tank of 2 year old gas which isn't doing it any favors, I was able to put about 2.5 gallons of fresh gas in the tank but its still an old mix. there was also 2 old mismatched spark plugs in it on my test drive which ive since replaced with 2 new bp8es. I read br8es is whats suggested but I had these on the shelf and they seem to run fine. ive found online the r is meant to shield electrical noise for radios and computers so I don't think that will be an issue. I think the boat is rated for about 430 lbs and between my friend and I we had probably 450lbs or so in it. would that extra weight, the old gas and 2 old mismatch spark plugs be enough to cut 1300rpm off the top end?
Anyways this motor/jet is used on early model wetbikes. I believe its a powerhead from a 82 dt50 going by pictures I found online. Now ive read someone with a similar boat will rev up to 6000rpm and he gets about 31mph from it. Can anyone think of anything on this motor I should look at that would impede performance? It starts extremely easy and sounds very smooth at idle. it does idle a bit high (2100ish rpm). Issues that im currently dealing with it has a full tank of 2 year old gas which isn't doing it any favors, I was able to put about 2.5 gallons of fresh gas in the tank but its still an old mix. there was also 2 old mismatched spark plugs in it on my test drive which ive since replaced with 2 new bp8es. I read br8es is whats suggested but I had these on the shelf and they seem to run fine. ive found online the r is meant to shield electrical noise for radios and computers so I don't think that will be an issue. I think the boat is rated for about 430 lbs and between my friend and I we had probably 450lbs or so in it. would that extra weight, the old gas and 2 old mismatch spark plugs be enough to cut 1300rpm off the top end?